不锈钢的钝化Passivation

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不锈钢管钝化方案

不锈钢管钝化方案

不锈钢管钝化方案不锈钢是一种具有强大抗腐蚀性能的材料,但在某些特定环境下,仍然会受到腐蚀的影响,降低其使用寿命和性能。

为了提高不锈钢管的抗腐蚀性能,可能需要采取钝化措施。

钝化是通过在不锈钢表面形成一层稳定的 passivation 层来防止腐蚀的过程。

本文将介绍几种常见的不锈钢管钝化方案。

一、酸洗钝化方案酸洗钝化是最常用的不锈钢管钝化方法之一。

主要步骤包括清洗、除油和酸洗。

清洗过程通常采用溶液或机械方式,以去除表面的杂质和尘土。

酸洗时一般使用盐酸或硫酸,将不锈钢管浸泡在酸液中一定时间,以去除氧化皮、锈迹和其他杂质,同时形成一层稳定的passivation 层。

二、电化学钝化方案电化学钝化是通过在不锈钢表面施加外加电场来形成 passivation 层的一种方法。

该方法一般需要在无氧环境中进行,常见的电化学钝化方法包括阳极极化和阴极保护。

阳极极化是通过施加阳极电压来氧化不锈钢表面,形成稳定的 passivation 层。

阴极保护是通过施加阴极电压来降低不锈钢管表面的氧化还原电位,从而减缓腐蚀的速度。

三、化学钝化方案化学钝化是利用化学反应来形成 passivation 层的方法。

其中,最常用的化学钝化方法是使用含有铬酸或硝酸的溶液进行处理。

在这个过程中,溶液中的铬酸或硝酸会与不锈钢管表面的铁原子发生反应,生成一层致密的铬酸盐或硝酸盐 passivation 层。

这层 passivation 层能够防止氧、水和其他腐蚀性物质进一步侵蚀。

四、机械钝化方案机械钝化是利用物理力学方法来提高不锈钢管抗腐蚀性能的一种技术。

该方法通过在不锈钢表面制造微观不平整,增加表面积,从而提高其抗腐蚀性。

机械钝化一般通过喷丸、砂皮或刷洗等方式实现。

对于不同的工程和应用场景,选择合适的不锈钢管钝化方案至关重要。

在选择之前,要充分了解钝化方案的工艺过程、适用范围和效果。

此外,注意合理使用并遵守环境保护要求。

正确的钝化方案能够提高不锈钢管的使用寿命和韧性,降低维护成本,并确保其在各种环境下的稳定性。

不锈钢部件的化学钝化处理的标准技术规范(精)

不锈钢部件的化学钝化处理的标准技术规范(精)

不锈钢部件的化学钝化处理的标准技术规范(中英文对照1. Scope1.范围1.1 This specification covers several different types of chemical passivation treatments for stainless steel parts. It includes recommendations and precautions for descaling, cleaning, and passivation of stainless steel parts. It includes several alternative tests, with acceptance criteria, for confirmation of effectiveness of such treatments for stainless steel parts.1.1本技术规范适用于几种不同类型不锈钢部件的化学钝化处理。

本技术规范包括:不锈钢部件除垢、清洁、钝化的建议和防护;本技术规范包括了几种可供选择的有验收标准的不锈钢部件处理效果确认的检测。

1.2 Practices for the mechanical and chemical treatments of stainless steel surfaces are discussed more thoroughly in Practice A 380.1.2 不锈钢表面物理和化学处理的作业在作业A380里有更详尽的论述。

1.3 Several alternative chemical treatments are defined for passivation of stainless steel parts. Appendix X1 gives some nonmandatory information and provides some general guidelines regarding the selection of passivation treatment appropriate to particular grades of stainless steel. It makes no recommendations regarding the suitability of any grade, treatment, or acceptance criteria for any particular application or class of applications.1.3 几种可供选择的不锈钢部件化学钝化处理在此有详细规定。

不锈钢钝化

不锈钢钝化

不锈钢钝化什么是不锈钢钝化?不锈钢钝化是指通过对不锈钢材料进行化学处理,在其表面形成一层致密的氧化膜,这种氧化膜能有效地防止不锈钢在潮湿、酸性或碱性环境中的腐蚀和氧化。

钝化处理可以提高不锈钢在各种环境中的耐蚀性和耐腐蚀性能,从而延长其使用寿命。

不锈钢钝化的原理不锈钢钝化的原理主要是通过在不锈钢表面形成氧化膜,使其具备了耐蚀性。

这种氧化膜主要由钝化剂中的氧气和金属表面的金属离子反应生成。

钝化剂中的氧气与金属表面的金属离子发生氧化还原反应,生成了一层致密的氧化膜。

这层氧化膜具有较高的电阻率和良好的耐腐蚀性,可以有效地阻隔外界的湿气和氧气对金属表面的腐蚀。

酸洗钝化法酸洗钝化法是一种常用的不锈钢钝化处理方法。

该方法通常使用稀硫酸、硝酸、氢氟酸等强酸作为钝化剂,将不锈钢材料浸泡在酸液中一定时间,使金属表面形成致密的氧化膜。

这种钝化方法处理后的不锈钢表面色泽光亮、平整,并具有较好的耐蚀性。

电解钝化法电解钝化法是一种利用电解原理将不锈钢材料表面氧化的方法。

该方法通过在不锈钢材料上施加一定电压,使其表面发生氧化反应,形成致密的氧化膜。

这种氧化膜具有均匀的厚度和良好的附着力,提高了不锈钢的耐蚀性和耐磨性。

化学钝化法化学钝化法是一种使用化学方法来进行钝化处理的方法。

该方法通常使用一些特殊的钝化剂,如漂白粉、磷酸、碱性钠钾氯酸盐等,将不锈钢材料浸泡在钝化液中一定时间,使其表面形成致密的氧化膜。

这种钝化方法具有成本低、操作简单等优点,适用于对不锈钢表面进行整体或局部的钝化处理。

不锈钢钝化广泛应用于各个领域,包括航空航天、汽车制造、化工、海洋工程、建筑等。

不锈钢钝化能提高不锈钢材料的耐腐蚀性,延长其使用寿命,减少维护保养成本。

在航空航天领域,不锈钢钝化可以增加飞机和宇航器的负载能力和载荷能力,提高其在恶劣气候环境中的耐用性。

在汽车制造领域,不锈钢钝化可以降低汽车零部件的腐蚀速度,延长汽车的使用寿命,提高车辆的质量和安全性能。

不锈钢加工专业术语

不锈钢加工专业术语

不锈钢加工专业术语不锈钢加工是一种常见的金属加工过程,涉及到许多专业术语。

在本文中,我们将介绍一些常见的不锈钢加工专业术语,以帮助读者更好地了解不锈钢加工过程。

1. 不锈钢(Stainless Steel):不锈钢是一种具有耐腐蚀性能的钢铁合金。

它主要由铁、铬、镍等元素组成,具有耐高温、耐酸碱等特性。

2. 拉伸(Tensile):拉伸是一种不锈钢加工方法,通过施加力来拉伸不锈钢材料,使其变形。

3. 折弯(Bending):折弯是一种不锈钢加工方法,通过施加力对不锈钢材料进行弯曲,使其呈现所需的形状。

4. 焊接(Welding):焊接是一种不锈钢加工方法,通过加热和施加压力将不锈钢材料连接在一起。

5. 切割(Cutting):切割是一种不锈钢加工方法,通过使用切割工具(如切割机、割炬等)将不锈钢材料切割成所需的形状。

6. 精密切割(Precision Cutting):精密切割是一种高精度的不锈钢加工方法,通过使用精密切割设备(如激光切割机)将不锈钢材料切割成所需的形状,能够实现更高的切割精度。

7. 钻孔(Drilling):钻孔是一种不锈钢加工方法,通过使用钻头将孔洞钻入不锈钢材料中。

8. 磨削(Grinding):磨削是一种不锈钢加工方法,通过使用磨削工具对不锈钢材料进行研磨,使其表面光滑。

9. 抛光(Polishing):抛光是一种不锈钢加工方法,通过使用抛光工具对不锈钢材料进行抛光处理,使其表面更加光滑、亮丽。

10. 镀膜(Coating):镀膜是一种不锈钢加工方法,通过在不锈钢材料表面涂覆一层保护性涂层,提高其耐腐蚀性能。

11. 铣削(Milling):铣削是一种不锈钢加工方法,通过使用铣削工具对不锈钢材料进行切削,使其表面呈现所需的形状。

12. 钝化(Passivation):钝化是一种不锈钢加工方法,通过对不锈钢材料进行酸洗处理,去除表面的氧化物和杂质,提高其耐腐蚀性能。

13. 冲压(Stamping):冲压是一种不锈钢加工方法,通过使用冲压模具对不锈钢材料进行冲压,使其呈现所需的形状。

不锈钢酸洗钝化操作规程-中英文应用版本

不锈钢酸洗钝化操作规程-中英文应用版本

不锈钢酸洗钝化操作规程-中英文应用版本------------------------------------------------------------------------------------------------不锈钢酸洗钝化操作规程-中英文应用版本不锈钢酸洗钝化规程目录TABLE OF CONTENTS1 编制方案的依据Basis of scheme compilation2 工作范围Working scope3 清洗工艺Cleaning process4 清洗过程Cleaning process5 废液处理Waste liquor treatment6 甲方提供的条件Condition supplied by the owner7 临时配管Temporary tubing8 检验与验收Test and accept9 安全2 2 23 7 7 8 8 9 1将生命注入产品让产品走向世界 1 编制方案的依据Basis of scheme compilation1.1 管道清洗的必要性Necessity of piping cleaning纯化水不锈钢管道在使用前,要进行脱脂、酸洗、钝化和消毒处理,管道才能达到生产使用的技术要求。

Before used stainless steel piping for purified water should bedegreased, pickled, passivity and disinfected. Only in this way can piping——————————————————————————————————————------------------------------------------------------------------------------------------------ meet technical needs of production and usage.1.2 《脱脂工程施工及验收规范》HG20202-2000。

不锈钢表面的防腐蚀--钝化

不锈钢表面的防腐蚀--钝化

不锈钢的抗腐蚀性能主要由于表面覆盖着一层极薄的(约1nm)致密的钝化膜,这层膜把腐蚀介质隔离,是不锈钢防护的基本屏障。

不锈钢钝化具有动态特征,不应看作腐蚀完全停止,而是形成扩散的阻挡层,使阳极反应大大降低。

通常在有还原剂(如氯离子)情况下倾向于破坏膜,而在氧化剂(如空气)存在时能保持或修复膜。

不锈钢工件放置于空气中会形成氧化膜,但这种膜的保护性不够完善。

通常先要进行彻底清洗,包括碱洗和酸洗,再用氧化剂钝化,才能保征钝化膜的完整性与稳定性。

酸洗的目的之一是为钝化处理创造条件,保证形成优质的钝化膜。

因为通过酸洗使不锈钢表面平均有10um厚一层表面被腐蚀掉,酸液的化学活性使得缺陷部位的溶解率比表面上其它部位高,因此酸洗可使整个表面趋于均匀平衡,一些原来容易造成腐蚀的隐患被清除掉了。

但更重要的是,通过酸洗钝化,使铁与铁的氧化物比铬与铬的氧化物优先溶解,去掉了贫铬层,造成铬在不锈钢表面富集,这种富铬钝化膜的电位可达+1.0V(SCE),接近贵金属的电位,提高了抗腐蚀的稳定性。

不同的钝化处理也会影响膜的成份与结构,从而影响不锈性,如通过电化学改性处理,可使钝化膜具有多层结构,在阻挡层形成CrO3或Cr2O3,或形成玻璃态的氧化膜,使不锈钢发挥最大的耐腐蚀性。

1.不锈钢酸洗钝化的必要性:奥氏体不锈钢具有良好的耐蚀性能,抗高温氧化性能,较好的低温性能及优良的机械与加上r生能。

因此广泛用于化工、石油、动力、核工程、航天航空、海洋、医药、轻工、纺织等部门。

其主要目的在于防腐防锈。

不锈钢的耐腐蚀主要依靠表面钝化膜,如果膜不完整或有缺陷,不锈钢仍会被腐蚀。

工程上通常进行酸洗钝化处理,使不锈钢的耐蚀潜力发挥得更大。

在不锈钢设备与部件在成形、组装、焊接、焊缝检查(如探伤、耐压试验)及施工标记等过程中带来表面油污、铁锈、非金属脏物、低熔点金属污染物、油漆、焊渣与飞溅物等,这些物质影响了不锈钢设备与部件表面质量,破坏了其表面的氧化膜,降低了钢的抗全面腐蚀性能和抗局部腐蚀性能(包括点蚀、缝隙腐蚀),甚至会导致应力腐蚀破裂。

不锈钢表面处理

不锈钢表面处理
49℃-60℃,20min 49℃-54℃,30min /
6
1.5.6表面处理标准—不锈钢钝化
Chemical Passivation Treatments(ASTM-A-967)
类别 class 描述 DESCRIPTION
Citric 1 Citric 2
Citric 3 Citric 4 Citric 5
电解抛光(Electropolishing)
原理
- 以工件为阳极,不溶性金属为阴极,在特定的电解液中,在通电的条 件下发生选择性溶解,从而达到微观整平,增大光亮度的效果
应用范围
- 生化,医药领域,食品,化妆,半导体,印刷,过滤,化工领 域
特性
- 1.色泽一致,清洁光亮,2.可以去除零件表面的毛刺3.提高零件 表面的耐蚀性,6.生产效率高,成本较低
60℃-71℃,20min 49℃-60℃,30min
21℃-49℃,20min / /
7
8
工件表面要保持平滑,不要有明显的凹痕.
热处理后的氧化皮要清除干净.表面渗碳,渗氮的零件不能进行钝化处理.
不要用铁及其氧化物做成的工具清理零件表面.
440C和S136材料,必须经过热处理,方可进行钝化
3
1.2.3不锈钢钝化—测试要求
沸水测试
硝酸 铁氰化钾测试
湿度测试
硫酸铜测试
盐雾测试
4
1.2.4不锈钢表面处理——电解抛光
深圳泰瑞电镀厂培训教材 ——不锈钢表面处理
Logo
1
1.2.1不锈钢钝化—原理

原理
不锈钢表面的金属成分与氧化性溶液发生反应,生成一层薄 的保护膜的过程。
●特点与用途
1.尺寸无变化

不锈钢 酸洗 钝化 标准

不锈钢 酸洗 钝化 标准

不锈钢酸洗和钝化是一种处理不锈钢材料的工艺,旨在去除表面污垢、氧化物和其他不纯物质,以提高不锈钢的耐腐蚀性能和美观度。

这些工艺通常受到一些国际和行业标准的指导,以确保安全和质量一致性。

以下是一些涉及不锈钢酸洗和钝化的标准:1. **ASTM A380/A380M - "Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems"**:这是美国材料和试验协会(ASTM)发布的标准,详细规定了不锈钢部件、设备和系统的清洁、去鳞和钝化过程。

它包括了材料的预处理、酸洗、钝化和检验等方面的指导。

2. **ASTM A967/A967M -"Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts"**:这个标准规定了用于不锈钢部件的化学钝化处理的要求和方法。

它描述了不同类型的钝化处理,例如4号、5号、6号和7号等。

3. **ISO 15730 -"Corrosion of metals and alloys –Cleaning of metals –Ultrasonic cleaning"**:这是国际标准化组织(ISO)发布的标准,涉及不锈钢等金属的超声波清洗方法。

超声波清洗通常是不锈钢酸洗过程的一部分,用于去除表面污垢。

4. **国家标准GB/T 3280 - "Stainless Steel Cold Rolled Steel Sheet and Strip"**:这是中国的国家标准,规定了不锈钢冷轧钢板和钢带的要求,包括其表面处理、质量和钝化要求。

5. **NACE SP0294 - "Design, Fabrication, and Inspection of Tanks for the Storage of Concentrated Sulfuric Acid and Oleum at Ambient Temperatures"**:这是由腐蚀工程师协会(NACE International)发布的标准,针对储存硫酸等强酸的储罐的设计、制造和检验提供了指南。

passvation成分

passvation成分

passvation成分
Passivation 是一种化学处理过程,用于使金属表面钝化,以减少腐蚀和氧化。

它通常用于处理不锈钢、铝、铜和其他金属材料。

在passivation 处理过程中,金属表面会形成一层保护膜,这层膜可以阻止金属与环境中的腐蚀性物质接触,从而延长金属的使用寿命。

Passivation 通常包含以下成分:
1. 硝酸:硝酸是passivation 处理中常用的强酸之一。

它可以与金属表面发生反应,形成一层保护膜。

2. 氟化物:某些passivation 处理过程中也使用氟化物,如氢氟酸。

氟化物也可以与金属表面发生反应,形成保护膜。

3. 其他酸类:例如硫酸、磷酸等酸类也可能在passivation 处理中使用。

4. 缓蚀剂:为了降低金属表面的腐蚀速率,通常会添加缓蚀剂。

缓蚀剂可以减缓腐蚀反应的速率,提高金属的耐腐蚀性。

5. 稳定剂:为了保持passivation 处理液的稳定性,通常会添加稳定剂。

稳定剂可以防止处理液中的成分发生分解或沉淀。

需要注意的是,不同的金属材料可能需要不同的passivation 处理配方。

因此,在使用passivation 处理时,应仔细阅读相关说明,并遵循制造商的建议。

不锈钢部件化学钝化处理的标准规范

不锈钢部件化学钝化处理的标准规范

时需要去除表面的硫化物以确保最大限度的提高耐腐蚀性。 3.1.1.2 在空气或其他氧化环境下,当不锈钢表面没有氧化铁皮和外源物质时其表面容易产 生防钝化层,更通俗的说法就是钝化。 3.1.1.3 化学处理方法,例如使用重铬酸钠溶液,更容易使没有氧化铁皮和外源物质的不锈 钢表面快速形成钝化层。此处理方法(在常用方法中有时也被称作钝化)在该标准规范中叫 做后清洗处理方法,用于区别与化学处理方法去除不锈钢表面游离铁的能力。 3.1.1.4 利用化学方法去除比锈钢表面的热色调或氧化铁皮和溶解不锈钢的能力叫做酸浸。 酸浸本质上比3.1.1.1中定义的钝化方法更加强势。酸浸处理过的不锈钢表面没有氧化铁皮、 游离铁和其他外源物质,也不像3.1.1.1中钝化时需要分别处理。3.1.1.2中的钝化过程不需 要进一步的化学处理,但是如果使用了3.1.1.3中的后清洗处理方法会提高效率。 3.1.1.5 电化学处理方法,包括利用电解和电镀的方法去除不锈钢表面的热色调或氧化铁皮 层和溶解不锈钢。使用该方法钝化比3.1.1.1中定义的方法更有效。通过这些方法处理过的 不锈钢表面没有氧化铁皮、游离铁和其他外源物质,也不像3.1.1.1中钝化时需要分别处理。 3.1.1.2中的钝化过程不需要进一步的化学处理,但是如果使用了3.1.1.3中的后清洗处理方 法会提高效率。关于化学处理方法的表述包括电化学处理方法,除非有其他特别的说明。
10. 后清洗处理方法
10.1 尽管不锈钢在空气或其他氧化环境下会自行形成钝化层,有具体要求时,操作者应该 采用能加快化学清洗处理过的不锈钢表面形成钝化层的化学处理方法。例如能加快钝化层的 形成但是不能去除不锈钢表面游离铁的媒介的溶液应该是重铬酸钠溶液。 10.2 如果用户要求,按照6.2,7.2,或8.3要求的方法进行最后漂洗后的一小时以内,所有铁 素体和马氏体钢部件必须浸泡在含有4-6%(重量百分比)重铬酸钠溶液的水溶液中,温度 控制在140-160华氏度(60-71摄氏度),至少浸泡30分钟。然后根据6.2,7.2或8.3条的要求 进行漂洗。最后使不锈钢部件充分干燥。 10.3 购买者会具体要求其他的后清洗处理方法。

不锈钢钝化原理(Theprincipleofstainlesssteelpassivation)

不锈钢钝化原理(Theprincipleofstainlesssteelpassivation)

不锈钢钝化原理(The principle of stainless steel passivation)The stainless steel workpiece is placed in the air to form an oxide film, but the protective coating is not perfect. It is usually necessary to thoroughly clean, including alkaline wash and pickling, and then use oxidant passivation to ensure the integrity and stability of the passivation film. One of the purposes of pickling is to create favorable conditions for passivation treatment to ensure the formation of high quality passivation film. Because by acid pickling surface of stainless steel with an average of 10 microns thick layer of surface corrosion, acid dissolving rate of defective parts of the chemical activity of higher than other parts on the surface, so the pickling can make the entire surface evenly balanced, some original cause corrosion hidden trouble was removed. But more importantly, through pickling passivation, made of iron and iron oxide ratio of chromium and chromium oxide priority to dissolve, remove the poor chromium layer, the surface enrichment of the chromium in stainless steel, the rich chromium passivation membrane potential can be up to + 1.0 V (SCE), close to the potential of precious metals, improve the stability of resistance to corrosion. Different passivation treatment also affect the composition and structure of the membrane, thus affecting stainless, such as by electrochemical modification, can make the passivation membrane has a multilayer structure, formed in the barrier layer CrO3 or Cr2O3, or glassy state of oxide film formation, make the most effectively with a stainless steel corrosion resistance.The study of 316L steel passivated film photoelectron spectroscopy (XPS) was introduced in Beijing. Passivation of stainless steel surface layer is dissolved and the adsorptionof water molecules, for some reason under the catalysis of oxidant, forming oxide and hydroxide, and with the composition of stainless steel reaction conversion of cr, Ni, Mo element, the final form stable phase into film, to prevent the damage of membrane and the occurrence of corrosion. The reaction process is:Fe, H20 + O * material [*] FeOH · O AD + H++ e[the] O * FeOH AD material [*] FeO · O AD + H++ e[*] FeO · O AD + H2O material FeOOH + O * 10 H++ e[FeO · O *] AD material FeO + O *FeOOH + Cr + H2O material CrOOH + Fe H202 feooh material Fe203 + H202 crooh material Cr203 + H20MO + 3 feo + 3 H2O material MOO3 + 3 fe · H2ONi + FeO + 2 H20 material NiO + Fe H20(including Os said the catalyst in the process of passivation and the passivation concentration remains unchanged, di Nie AD said adsorption intermediate.) [page]It can be seen that the top layer of 316L passivation film is Fe2O3, Fe (OH) 3, or gamma-feooh, Cr203, CrOOH or Cr (OH) 3,MO is in MOO form, and the main components of passivation film are CrO3, FeO and NiO.Objective: to improve corrosion resistance of stainless steel and prevent corrosion of materialsRange: all stainless steel welding partsResponsible: director of electric welding personnel equipment of power workshopApplication:1. The process of pickling passivation is as follows:Acid washing, flushing, passivationPreprocessing - - - rinseAcid wash passivation (two in one) paste1.1 before processing1.1.1 remove spatter, welding slag, edge and concave inequality of welds and mother materials.1.1.2 remove oil stains, and use2.5% Na3PO4 base wash alkaline wash when necessary. After alkaline wash, wash the surface with clean water.Acid wash and rinse1.2.1 preparation of pickling pasteUsing nitric acid (HNO3), hydrochloric acid (HCL) and water according to 2:1:7 proportion of the solution,Press 1:9 with dextrin powder and add talcum powder to paste.1.2.2 plaster and rinseApply the paste evenly to the area where the acid is needed at room temperature. After 40 to 60 minutes, remove the paste and rinse off with water so that the surface does not retain the residue. (disassembly of the carbon steel on the product that is used for pickling products, such as the undetachable need for protective paint or sealing rubber)1.3 passivation and flushing1.3.1 the preparation of passivationMix it with nitric acid (HNO3) and hydrochloric acid (HCL) according to the proportion of 6:4, and then mix with dextrin powder 1:9 to add talcum powder to paste.1.3.2 paste passivation and flushingApply the paste to the acid wash at room temperature, after 2-3 hours, remove the paste, then rinse with water, leaving the surface without residue.4 pickling passivation (two-in-one) paste (paint brush) and rinse1.4.1 apply the paste evenly to the surface of the need of the passivation of the acid. The thickness of the oxide coating can be slightly thicker.1.4.2 according to the requirements of the passivation instructions, the passivation paste should be kept for 5-30 minutes according to the thickness of the raw materials.1.4.3 wipe away the rust and oxide with a cotton yarn or towel before the cream is dry. (if necessary, use a stainless steel wire brush or wire brush).1.4.4 rinse the surface thoroughly until the surface is evenly silvery white.2. The quality inspection of pickling passivation2.1 appearance inspectionThe surface of pickling passivation should be uniformly silvery white, no obvious corrosion marks, no oxidation color on the surface of the weld and heat affected area, no uneven stain of color.2.2 residue testThe pH value of the residual liquid on the surface was considered to be qualified by the phenolphthalein test.The production process of the color masterbatch is strict, and the wet process is generally adopted. The color masterbatch is made by grinding, rotating, washing, drying and granulating with water. Only in this way can the quality of the product be guaranteed. Pigment in grinding processing at the same time, also should undertake a series of tests, such as determination of sand slurry fineness, determination of the spread of the abrasive slurry performance, determining the solid content of sand slurry and determination of printing ink fineness, etc.There are four methods for the process flow of color masterbatch production:(1) the ink method: as the name implies, it is the production method of printing ink in the production of the chroma grain, which is the coating of a layer of low molecular protection on the surface of the pigment by three rolls of grinding. After grinding, the pulp is mixed with the carrier resin, then plasticized by a two-roll plastic mixer (also known as a double roll machine), and finally the granulation is made by single screw or double screw extruder.The process is as follows:The ingredients are mixed with coarse and coarse pulp and the two rollers of fine pulp are extruded(2) flushing method: it is the pigment, water and dispersing agent through sanding, so that the pigment particles are less than 1 mu m, and by phase transfer method, the pigment istransferred to the oil phase, and then the color masterbatch is dried. The rotating phase requires the use of organic solvents and corresponding solvent recovery devices. Its process is as follows:The thin slurry rinses the evaporative concentrate drying and adding the granules(3) it is legal to knead the pigment and the oil carrier, and use the characteristic of the pigment to oil the pigment from the water to the oil phase. The surface of the pigment is covered by an oil carrier.The pigment disperses stability to prevent pigment from condensing.(4) metallic soap: paint after grinding granularity reaches 1 mu m or so, and join the soap under a certain temperature, make each pigment particle uniform surface wetting by soap, forming a layer of saponification liquid, when metal salt solution With the paint surface after join the saponification reaction and generate a layer of protective layer of metallic soap (magnesium stearate), it makes after grinding fine pigment particles will not cause flocculation phenomenon, and protect certain fineness。

不锈钢表面工艺种类

不锈钢表面工艺种类

不锈钢表面工艺种类
不锈钢表面工艺种类有很多种,其中一些常见的包括:
1. 镜面抛光:利用机械力和化学药剂,将不锈钢表面抛光成高光泽的镜面效果。

2. 钝化(Passivation):在不锈钢表面形成一层保护性的氧化膜,提高耐腐蚀性和抗氧化性能。

3. 喷砂(Sandblasting):通过高速飞沙打磨,使不锈钢表面呈现出一种粗糙、均匀的效果。

4. 电镀:通过在不锈钢表面镀上一层金属膜,如镀铬、镀镍、镀锌等,改善表面硬度和耐腐蚀性。

5. 漆涂:在不锈钢表面涂上一层油漆,可以提供颜色选择和额外的保护。

6. 氧化(Anodizing):通过电解过程形成一层氧化膜,增加不锈钢的耐腐蚀性和硬度。

这些表面工艺可以单独应用或结合使用,以满足不同的功能和美观要求。

不锈钢钝化passivation

不锈钢钝化passivation

METAL FINISHING SOLUTIONS BEYOND THE SURFACE PASSIVATION OF STAINLESS STEELPassivation of Stainless SteelGetting the Properties You've Paid Forby Dan Englebert, Vice President Technical ServicesImagineering Enterprises, Inc.The conversation usually starts out something like this:“Hey, this is Joe from Joe's Machine Shop.We've got a job in here we're working on and the customer wants us to have some kinda passivate coating something-or-other.Y ou guys do that? How thick is that stuff? Is that like some kinda plating or paint or something? What color is it? How much tolerance should I allow for it?”Usually, the opening statement ends with a phrase like, “I don't even know why they need it.What's the point of using stainless steel if your gonna put some kinda coating on it anyway?”The fact of the matter is, “Joe”is not the exception.Many machine shops, purchasing agents, and engineers alike are somewhat in the dark when it comes to the relationship between corrosion resistant (stainless) steel and chemical passivation.Even among the metal finishing community, there is some disagreement about the theory behind the process of chemical passivation.Some believe it is effective because it is a cleaning process.Others credit the enhanced corrosion resistant properties to the thin, transparent oxide film resulting from chemical passivation.Regardless of the argu-ment, the bottom line is, it works! Verification tests, including copper sulfate immersion, and accelerated corrosion tests, such as salt spray, high humidity, and water immersion, undisputedly confirm the effectiveness of chemical passivation.Advanced material engi-neers in aerospace, electronics, medical, and similar high-tech industries have utilized chemical passivation for many years.Their applications demand the maximum perform-ance from components manufactured from corrosion resistant (stainless) steels, and they realize that passivation is one of the most effective methods of achieving the desired results.What is Passivation?According to ASTM A 380, passivation is “the removal of exogenous iron or iron com-pounds from the surface of a stainless steel by means of a chemical dissolution, most typically by a treatment with an acid solution that will remove the surface contamination but will not significantly affect the stainless steel itself.”In addition, it also describes pas-sivation as “the chemical treatment of a stainless steel with a mild oxidant, such as a nitric acid solution, for the purpose of enhancing the spontaneous formation of the pro-tective passive film.”In layman's terms, the passivation process removes “free iron”contamination left behind on the surface of the stainless steel as a result of machining and fabricating processes. These contaminants are potential corrosion sites which, if not removed, result in prema-ture corrosion and ultimately result in deterioration of the component.In addition, thepassivation process facilitates the formation of a very thin, transparent oxide film, which protects the stainless steel from “selective”oxidation (corrosion).So what is passivation?Is it cleaning? Is it a protective coating? In my opinion, it is a combination of both!How is the Passivation Process Performed?The process typically begins with a thorough cleaning cycle.It is intended to remove oils, greases, forming compounds, lubricants, coolants, cutting fluids, and other undesirable organic and metallic residue left behind as a result of fabrication and machining processes.General degreasing and cleaning can be accomplished by a variety of com-monly accepted methods, including vapor degreasing, solvent cleaning, and alkaline soaking.After removal of the organic and metallicresidues, the parts are placed into theappropriate passivation solution.Althoughthere are many variations of passivatingsolutions, the overwhelming choice is stillthe nitric acid based solutions.Recently,there has been substantial research per-formed to develop alternative processesand solutions that are more “environmen-tally friendly,”yet equally effective.Althoughalternative solutions containing citric acidand other types of proprietary chemistryare available, they have not been aswidely accepted commercially as nitricacid based solutions.The three major variables that must be considered and controlled for the passivation process selection are time, temperature, and concentration.T ypical immersion times are between 20 minutes and 2 hours.T ypical bath temperatures range between room temperature and 160°F .Nitric acid concentrations in the 20% to 50% by volume range are generally specified.Many specifications include the use of sodium dichromate in the passivation solution, or as a post passivation rinse, to aid in the formation of a chromic oxide film.Careful solution control, including water purity, ppm (parts per million) of metallic impurities, and chemical maintenance, is crucial for success.The type of stainless steel being processed is the determining factor when selecting the most effective passivation process.Bath selection (time, temperature, and concen-tration) are all a function of the type of alloy being processed.A thorough knowledge of the material types and passivation processes is paramount to achieving the desired results.Conversely, improper bath and process selection and/or process control will produce unacceptable results, and in extreme cases, can lead to catastrophic failure,including extreme pitting, etching and/or totaldissolution of the entire component.TWO-HOUR salt spray test per ASTM B-117.With passivation on the left and without on the right.Equipment and PrecautionsPassivation should only be performed by trained, experienced technicians familiar with the potential hazards associated with the science.Safety practices must be fully under-stood when handling passivation chemicals.Special boots, gloves, aprons and other safety equipment must be utilized.T anks, heaters and ventilation, as well as baskets and racks, must be appropriately engineered to perform the process.Iron or steel parts or equipment must never be introduced to the process, or the results can be devastat-ing! Furthermore, in order to comply with EPA requirements, the necessary water and air permits and treatment capabilities must be in place.The days of the “mom-and-pop”shops performing passivation in a stone crock in the back corner of the shop are dimin-ishing, due to safety and environmental concerns.Specifications and Verification TestingThere are a few generally accepted industry specifications available for reference when choosing a passivation process.They offer time, temperature, and concentration infor-mation, and subsequent testing requirements to validate the effectiveness of the process. Many large corporations have developed internal specifications to control their unique requirements regarding passivation and verification testing.Regardless of the situation, it is usually prudent to reference a proven procedure when requesting passivation.By referencing a specification, you don't have to “reinvent the wheel,”and by taking advan-tage of the past experiences of others, both successes and failures, you can eliminate much of the guesswork that would otherwise accompany a new process.Although recently cancelled, the most commonly referenced industry specifications regarding passivation are Fed.Spec.QQ-P-35C, which is now superseded by ASTM A-967, and ASTM A-380.All three are well written, well defined documents which pro-vide guidance on the entire process, from manufacturing to final testing requirements.If you're not sure what you need, they can be referenced in full, or selectively.The testing requirements can be utilized or waived, depending upon the individual situation.One of the most commonly specified verification tests is the copper sulfate test. Passivated parts are immersed in a copper sulfate solution for 6 minutes, rinsed, and visually examined.Any copper (pink) color indicates the presence of free iron, and the test is considered unacceptable.Other validation tests include a 2 hour Salt Spray or24 hour high-humidity test.These tests are performed by placing passivated parts ina highly controlled chamber which creates an accelerated corrosive environment.After subjecting the test pieces to the corrosive atmosphere for the prescribed exposure periods, the parts are removed and evaluated.Although results can be somewhat subjective, ASTM B-117 is an excellent reference in determining acceptability.It is important to note that each of the test methods mentioned have different advantages and limitations.Care should be taken to select the appropriate test methods, based on alloy type and end use environment.Machining and Heat Treating TechniquesPerhaps the most overlooked variable in the entire passivation equation is the negative impact of poor machining and heat treating practices.All too often, gross contamination introduced during manufacturing and/or thermal processes leads to unacceptable test results.The following practices will reduce gross contamination during manufacturing and increase the chances of successful passivation and test results:* Never use grinding wheels, sanding materials, or wire brushes made of iron, iron oxide, steel, zinc, or other undesirable materials that may cause contamination of the stainless steel surface.* The use of carbide or other non-metallic tooling is recommended whenever possible.* Grinding wheels, sanding wheels, and wire brushes that have been previously used on other metals should not be used on stainless steel.* Use only clean, unused abrasives such as glass beads or iron-free silica or alumi-na sand for abrasive blasting.Never use steel shot or grit, or abrasives which have been used to blast other materials.* Thorough cleaning prior to any thermal processing is critical! Stress relieving,annealing, drawing, or other hot-forming processes can actually draw surface contami-nants deeper into the substrate, making them almost impossible to remove during pas-sivation.* Care should be taken during all thermal processes to avoid the formation of discol-oration (oxides).Passivation is not designed to remove discoloration, and will not pene-trate heavy oxide layers.In extreme situations, additional pickling and descaling opera-tions are required prior to passivation to remove the discoloration.Controlled atmosphere ovens are highly recommended for all thermal processes to reduce airborne contamination and prevent oxides from developing.So how does this happen?Stainless steel parts are supposed to berust-resistant.ConclusionsSo how do you get “the performance you'vepaid for”from high-dollar stainless steelalloys? It really boils down to a basic under-standing that the passivation process is bothan art and a science, and that machining,fabricating, and heat treating practices cansubstantially affect the corrosion resistanceof the component.It's a well known fact thatpassivation will enhance the corrosionresistance of stainless steels, but to realizethe maximum performance from these high-tech alloys, all parties involved with manu-facturing must understand their responsibili-ty in maintaining the integrity of the materialthroughout the process.About the Author:Dan Englebert is the Vice-President, T echnical Services at Imagineering Enterprises,Inc., a metal finishing and consulting firm located in South Bend, Indiana.TheQS-9000/ISO 9002 certified company was founded in 1959 and is recognized globally as an Electroless Nickel Plating expert source.Imagineering is a member of the National Association of Metal Finishers (NAMF) and the Indiana Association of Metal Finishers (IAMF).Englebert is a member of the American Electroplaters and Surface Finishers Society (AESF) and the National Association of Corrosion Engineers (NACE).References1. ASTM A 380 - 96 Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems * ASTM Committee A-1 on Steel, Stainless Steel, and Related Alloys* ASTM Committee on Standards100 Barr Harbor DriveWest Conshohocken, PA 194282. Fed. Spec. QQ-P-35C October 28, 1988 Passivation Treatments For Corrosion Resistant Steel* CANCELLED April 4, 1997* SUPERSEDED by ASTM A 967 - 96Copper Sulfate test per MIL-STD-753.With passivation on left and without on right.3. ASTM A 967 - 96 Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts * ASTM Committee A-1 on Steel, Stainless Steel, and Related Alloys* ASTM Committee on Standards100 Barr Harbor DriveWest Conshohocken, PA 194284. ASTM B 117 - 95 Standard Practice for Operating Salt Spray (Fog) Apparatus* ASTM Committee G-1 on Corrosion of Metals* ASTM Committee on Standards100 Barr Harbor DriveWest Conshohocken, PA 19428。

VOPOX不锈钢钝化剂.doc

VOPOX不锈钢钝化剂.doc

VOPOX不锈钢钝化剂
产品编号:VOPOX Passivation
适用范围:不锈钢钝化剂适用于不锈钢工件经机械处理后(例如:研磨、刷擦、拉丝、抛光或喷砂等),需要修复不锈钢表面被破坏的富铬保护膜;或经酸洗处理后仍需要提高耐腐蚀性的不锈钢工件。

使表面立刻形成新的富铬钝化保护膜,提高不锈钢件表面防腐质量。

使用方法:通过浸泡、喷淋、刷洗等方法使不锈钢钝化剂作用于工件表面或工件整体,一定的作用时间后(约5-10分钟)用高压水彻底冲洗。

产品特点:操作简便、安全。

钝化效果优异。

不锈钢304酸洗钝化配方

不锈钢304酸洗钝化配方

不锈钢304酸洗钝化配方一、引言不锈钢304是一种常用的不锈钢材料,具有良好的抗腐蚀性能和机械性能。

然而,在一些特殊应用环境下,不锈钢304可能会出现表面氧化、腐蚀或污染等问题。

为了解决这些问题,可以采用酸洗钝化的方法进行处理。

本文将介绍不锈钢304酸洗钝化的配方及其工艺流程。

二、酸洗钝化配方1. 酸洗液配方:- 硝酸:300 g/L- 硫酸:50 g/L- 氢氟酸:20 g/L- 水:适量2. 钝化剂配方:- 铬酸:200 g/L- 硫酸:20 g/L- 水:适量三、工艺流程1. 表面预处理:将不锈钢304表面的油污、灰尘等杂质清洗干净,可以使用碱洗液进行清洗。

2. 酸洗处理:- 将酸洗液配制好,并搅拌均匀。

- 将不锈钢304浸入酸洗液中,注意控制酸液的温度和浸泡时间。

一般情况下,酸液温度控制在40-60℃,浸泡时间为10-30分钟。

- 酸洗后,用清水彻底冲洗不锈钢304,并将其表面水分抹干。

3. 钝化处理:- 将钝化剂配制好,并搅拌均匀。

- 将酸洗后的不锈钢304浸入钝化液中,注意控制钝化液的温度和浸泡时间。

一般情况下,钝化液温度控制在20-40℃,浸泡时间为5-15分钟。

- 钝化后,用清水彻底冲洗不锈钢304,并将其表面水分抹干。

四、注意事项1. 在酸洗和钝化过程中,应戴上防酸碱手套、护目镜等个人防护装备,避免对人体造成伤害。

2. 酸洗液和钝化液配制时,应按照一定的比例进行调配,避免过量使用或浪费。

3. 在酸洗和钝化过程中,要控制好液体的温度和浸泡时间,避免对不锈钢304产生过度腐蚀或不足的效果。

4. 酸洗和钝化后,应及时用清水冲洗不锈钢304,以去除残留的酸液和钝化液,防止二次腐蚀的发生。

五、结论不锈钢304酸洗钝化是一种常用的表面处理方法,可以有效提高不锈钢304的耐腐蚀性能和美观度。

通过合理配制酸洗液和钝化液,控制好处理过程中的温度和浸泡时间,可以获得良好的处理效果。

然而,在实际应用中,还需要根据具体情况进行调整和优化,以满足不同的要求和需求。

钝化 passivation

钝化  passivation

钝化passivation1、钝化的概念passivation conception采用特殊的溶液让金属表面生成一层致密的氧化膜,钝化是使金属表面转化为不易被氧化的状态,而延缓金属的腐蚀速度的方法。

Passivation of stainless steel is basically the removal of exogenous materials and iron from the surface, thereby "chromium enriching" the surface. This is followed by oxidation of the chromium to form a corrosion resistant layer of chrome oxide on the surface. The purpose of the passivation is to increase the amount of time before corrosion, decrease the corrosion speed on the surface.2、钝化的作用:passivation function防腐蚀/防氧化变色corrosion protection/prevent oxidation stain3、钝化的实施理由:why need passivation电镀后产品经酸洗、水冲洗、漂洗后、金属表面很清洁,非常活化,很容易遭受腐蚀,所以要立即进行钝化处理,使清洗后的金属表面生产保护膜减缓腐蚀.Plated product by acid bath, water bath、rinsing, it’s very clean on the surface, easy to corrosion. So it need passivation treatment after plating immediately,Passivation film on the surface to protect the parts decrease corrosion.4、钝化处理的时机when to passivation treatment电镀后立即实施钝化Passivation treatment after plationg immediatley5、钝化的原理Passivation theory其钝化的机理可用薄膜理论来解释,即认为钝化是由于金属与氧化性质作用,作用时在金属表面生成一种非常薄的、致密的、覆盖性能良好的、牢固地吸附在金属表面上的钝化膜。

不锈钢的钝化原理

不锈钢的钝化原理

不锈钢的钝化原理宝子们,今天咱们来唠唠不锈钢钝化这个超有趣的事儿。

你看啊,不锈钢这玩意儿,咱们日常生活里到处都是,锅碗瓢盆啦,建筑材料啦,那家伙,老常见了。

不锈钢之所以叫不锈钢,是因为它本身就比较耐腐蚀,但是呢,它还有个更厉害的技能,就是钝化。

不锈钢钝化啊,就像是给不锈钢穿上了一层超级隐形的防护服。

这层防护服是咋来的呢?其实啊,不锈钢的表面有一层很薄很薄的氧化膜。

这层氧化膜可不得了,它是不锈钢钝化的关键所在。

在自然环境中呢,不锈钢表面就会和空气中的氧气发生反应,慢慢形成这层氧化膜。

但是呢,这种自然形成的氧化膜有时候还不够强大。

当我们进行钝化处理的时候呢,就像是给不锈钢请了个超级保镖来强化这层保护膜。

一般来说,钝化处理是用一些化学试剂来处理不锈钢表面。

这些化学试剂就像是一群勤劳的小工匠,它们跑到不锈钢表面,和那些容易被腐蚀的成分发生反应。

比如说,不锈钢里的铁元素,要是没有这层钝化膜保护,就很容易和外界的酸啊、碱啊之类的东西反应,就像一个没穿铠甲的小战士,很容易受伤。

这时候,钝化处理后的氧化膜就把铁元素这些容易被攻击的地方都给保护起来了。

这层膜的结构很特别,它非常致密,就像一个严严实实的小城堡,把里面的金属都圈在里面,不让外面那些坏家伙,像腐蚀性的物质啊,轻易进去。

而且呢,这层膜还有自我修复的能力哦。

要是不小心有一点点小破损,它就会像小超人一样,自己慢慢修复好。

咱再打个比方,不锈钢就像一个可爱的小房子,钝化膜就是房子外面那层坚固又漂亮的外墙。

这外墙不仅能挡住风雨,还能挡住那些想破坏房子的小怪兽,也就是腐蚀性物质。

如果没有这层钝化膜,不锈钢这个小房子就很容易被腐蚀得破破烂烂的,就不好看也不实用啦。

你想啊,要是咱们家里的不锈钢锅没有这层钝化膜,每次煮个酸溜溜的汤,锅就被腐蚀得坑坑洼洼的,那多闹心啊。

有了钝化膜,就可以放心大胆地煮各种美食啦。

而且哦,不锈钢钝化还能让不锈钢的表面更加美观。

就像给它化了个精致的妆一样,表面看起来更加光滑、均匀,摸起来手感也更好。

不锈钢部件的化学钝化处理的标准技术规范(精)

不锈钢部件的化学钝化处理的标准技术规范(精)

不锈钢部件的化学钝化处理的标准技术规范(中英文对照1. Scope1.范围1.1 This specification covers several different types of chemical passivation treatments for stainless steel parts. It includes recommendations and precautions for descaling, cleaning, and passivation of stainless steel parts. It includes several alternative tests, with acceptance criteria, for confirmation of effectiveness of such treatments for stainless steel parts.1.1本技术规范适用于几种不同类型不锈钢部件的化学钝化处理。

本技术规范包括:不锈钢部件除垢、清洁、钝化的建议和防护;本技术规范包括了几种可供选择的有验收标准的不锈钢部件处理效果确认的检测。

1.2 Practices for the mechanical and chemical treatments of stainless steel surfaces are discussed more thoroughly in Practice A 380.1.2 不锈钢表面物理和化学处理的作业在作业A380里有更详尽的论述。

1.3 Several alternative chemical treatments are defined for passivation of stainless steel parts. Appendix X1 gives some nonmandatory information and provides some general guidelines regarding the selection of passivation treatment appropriate to particular grades of stainless steel. It makes no recommendations regarding the suitability of any grade, treatment, or acceptance criteria for any particular application or class of applications.1.3几种可供选择的不锈钢部件化学钝化处理在此有详细规定。

不锈钢酸洗钝化流程

不锈钢酸洗钝化流程

不锈钢酸洗钝化流程英文回答:Stainless Steel Pickling and Passivation Process.Introduction.Stainless steel is an alloy of iron that contains at least 10.5% chromium and less than 1.2% carbon. The chromium content makes the steel resistant to corrosion and rust. Pickling and passivation are two processes that are used to improve the corrosion resistance of stainless steel.Pickling.Pickling is a process that removes oxides, scale, and other contaminants from the surface of stainless steel.This is typically done by immersing the steel in a solution of hydrochloric acid or nitric acid. The acid reacts withthe oxides and scale, dissolving them and leaving a cleansurface.Passivation.Passivation is a process that creates a thin,protective layer of chromium oxide on the surface of stainless steel. This layer is what makes the steel resistant to corrosion. Passivation is typically done by immersing the steel in a solution of nitric acid or a mixture of nitric acid and sulfuric acid. The acid reacts with the surface of the steel, forming a chromium oxide layer.Benefits of Pickling and Passivation.Pickling and passivation offer a number of benefits for stainless steel, including:Improved corrosion resistance.Reduced surface roughness.Enhanced appearance.Increased weldability.Process Steps.The pickling and passivation process typically involves the following steps:1. Cleaning: The stainless steel is cleaned to remove any dirt, grease, or other contaminants.2. Pickling: The stainless steel is immersed in a solution of hydrochloric acid or nitric acid.3. Rinsing: The stainless steel is rinsed with water to remove any residual acid.4. Passivation: The stainless steel is immersed in a solution of nitric acid or a mixture of nitric acid and sulfuric acid.5. Rinsing: The stainless steel is rinsed with water to remove any residual acid.6. Drying: The stainless steel is dried to prevent rusting.Safety Precautions.Pickling and passivation are hazardous processes that must be carried out by trained personnel. The following safety precautions should be taken:Wear appropriate personal protective equipment, including gloves, goggles, and a respirator.Use proper ventilation to prevent exposure to acid fumes.Handle acids with care and dispose of them properly.中文回答:不锈钢酸洗钝化工艺。

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IMAGINEERING
金属表面处理解决方案
不锈钢的钝化
作者:Dan Englebert,技术服务副总监
Imagineering有限公司
对话通常是这么开始的:“你好,我是来自某公司的某人,现在我们有一项工作,客户希望我们做一些钝化涂层的活儿,你们可以做吗?涂层的厚度是多少呢?这和电镀、喷漆等其他表面处理一样吗?处理后是什么颜色?我可以得到的公差范围是多少?”通常情况下,这样开放式的对话以一句简单的话语,比如“我都不知道这样是否有必要,如果你在不锈钢上还要涂层,要不锈钢做什么呢?”
事实上,这个某公司的某人不是唯一的一个例外,许多机加车间、采购商、甚至工程师,在碰到不锈钢防腐和化学钝化的关系时,都了解不多。

甚至在金属表面处理行业,仍存才对化学钝化工艺理论的分歧意见。

有人认为其效果明显,因为过程工艺很清洁;有人认为通过化学钝化产生的薄薄的一层透明的氧化膜可以增强防腐能力。

无论怎么争论,这个效果的底线是,它确实有用!各种验证试验,包括硫酸铜浸浴、加速腐蚀测试、盐雾试验、高湿度和水浸泡,都毫无争议的证明化学钝化的有效性。

在航空航天、电子、医药以及类似高技术领域里的高级工程师已经使用化学钝化这种工艺多年了,这些行业的应用需要零部件有很好的不锈钢防腐性能,他们认为钝化是得到想要的结果的最有效的办法之一。

什么是钝化?
根据ASTM A380的描述,钝化是指使用化学稀释溶解的办法,去除不锈钢表面的外来铁质或铁化合物,尤其是,通过酸化去除不锈钢表面的锈蚀,但是对不锈钢本身不造成任何影响。

另外,钝化也可以定义为“用中度氧化剂,例如硝酸溶液,对不锈钢进行表面处理,用于增强惰性保护膜的自发形成”。

在外行人看来,钝化的过程就是去除不锈钢表面的游离铁质,将加工表面显现出来。

这些游离的铁质是潜在的腐蚀成分,如果不去掉,可能会造成永久腐蚀,最终导致零部件的退化和变质。

另外,钝化的工艺过程有助于薄而透明的氧化膜的形成,可以有效的保护不锈钢表面的有选择性的氧化腐蚀。

因此,什么是钝化?它干净吗?它是保护性涂层吗?以我看来,他是两种工艺的结合。

钝化的过程
钝化的过程从全面清洁开始,目的是去除表面的油脂、形成性化合物、润滑剂、冷却剂和其他没用的有机物和金属残余;一般的除油和清洁可以通过各种通用方法来完成,包括蒸汽、溶液、碱液浸泡等。

去掉有机物和金属残留后,将零件放在适当的钝化液里,尽管有很多钝化液,我推荐的是硝酸基溶液。

最近,很多研究都在进行,目的是开发一种更环保的替代型钝化液,但是,效果不佳。

尽管替代型钝化液里包含柠檬酸和其他专利的化学物质,但是与硝酸基溶液比起来,后者应用更加广泛和商业化。

根据ASTM B-117进行2小时盐雾试验,左边的钝化处理,右边的没有钝化处理
钝化的过程中,有三个必须要考虑和控制的变量:时间、温度和浓度。

浸泡时间为20分钟到2个小时不等,浸泡温度范围在室温和华氏160°之间,硝酸溶液的体积浓度在20%到50%之间。

很多规范还在钝化液里使用重铬酸钠,或作为钝化后的清洗液,以帮助形成氧化铬薄膜。

小心地对溶液进行控制,包括水的纯度、金属杂质的ppm,以及化学维护,对钝化效果都很重要。

要处理的不锈钢的类型不同,选择的钝化工艺也不一样。

对三个关键因素的选择是处理的关键。

要得到理想的钝化结果,需要对材料的类型和钝化工艺有充分的了解。

否则,错误的控制将导致不良结果,极端情况下,可能会造成灾难性的失败,包括麻点腐蚀、刻蚀或者整个零部件在溶液内完全溶解。

设备和预防措施
钝化的过程只能由经过培训、有经验的技师来做,要对安全操作有完全的理解。

特殊的靴子、首套、围裙以及其他安全设施都必不可少。

容器、加热器和通风,以及篮筐、支架都要一应俱全,保证工艺实施。

铁或钢件或设备绝对不能用在钝化工程和工艺当中,否则,结果会是毁灭性的。

而且,为了符合环保的要求,对水、空气的处理设施都应当到位。

现在,随着对安全环境的关注,作坊式的钝化场所已经逐渐消失了。

规范和验证试验
在选择钝化工艺时,有几种普遍接受的行业规范,规范里有时间、温度和浓度等信息,包括验证工艺有效性的测试设备。

很多大企业也开发了自己的内部使用规范,来控制独特的钝化效果和并进行验证试验。

无论现状如何,在进行钝化工作时,一般都会小心的找一个证明可靠的规程作为参照,有了参照,就可以避免重蹈覆辙,通过过去的经验借鉴,可以避免更多的猜想和摸着石头过河的工作。

最近取消了Fed. Spec. QQ-P-35C这个通用行业规范,取而代之的是ASTM A-967和ASTM A-380。

所有的规范都已经写进文件,并做了很好的规定,从生产到最终的测试要求,对整个工艺起到指导作用。

如果不确定你想要什么,可以完全参考,或有选择的参考。

根据个体的情况,选择检测要求或不用。

检测当中,最普遍规定的是硫酸铜测试。

需要钝化的部分浸泡在硫酸铜溶液里6分钟,进行漂洗检查。

铜的颜色(粉色)显示游离铁质的存在,这个测试是不能接受的。

其他测试包括2个小时的盐雾试验或24小时的高湿度试验,这些试验是将需要钝化的零部件放在一个高度可控的房间里,产生一个可以加速腐蚀的环境,经过上述的过程后,将试件从试验环境中取出来,进行评估。

尽管结果有些主观,但是ASTM B-17可以作为是否可以接受的很好的参考。

注意:每个测试方法都有不同的优点和限制,要根据材料类型和使用环境进行适当的测试方法的选择。

机加工和热处理技术
或许在整个钝化程式重,最容易忽视的变数就是机加工质量和热处理工艺造成的负面影响。

经常地,机加工和热处理期间的总体影响会导致测试结果不合格。

以下的方法和措施可以减少加工过程的总体影响,并增加钝化成功和测试结果合同的几率:
不锈钢应当是不会产生锈蚀的那么,这些锈蚀是怎么产生的呢?
-不要使用砂轮、打磨材料或铁、氧化铁、或钢制的钢丝刷,或其他可能造成不锈钢表面污染的材料;
-如果可能,推荐使用碳化物或其他非金属工具;
-在其他材料上使用过的砂轮、钢丝刷等不要再在不锈钢上面使用;
-打磨喷砂时,只使用清洁的、为使用过的磨料,例如玻璃球、无铁硅石、或刚玉砂;
-热处理前,要对零部件进行全面清理,这一点很重要。

消除应力、退火、拉伸或其他热成形工艺都可能实际使表面的污染物质进入更深的表面内,之后,再要去除这些污染杂质,几乎不可能;
-在热处理时,需要注意变色(氧化)的形成,钝化不是要去除变色,也不是要深入氧化层。

在极端条件下,为了去除变色层,需要在钝化前进行一些剥皮或去鳞的作业。

热处理时,推荐使用可控温电炉,以减少空气污染,防止氧化的深入发展和影响。

结论
所以,你付了钱,如何才能得到物有所值的东西呢?这真的可以归结为一种基本的说法:钝化工艺时艺术和科技的结合,机加工、制造、以及热处理方法在很大程度上都能影响零部件的抗腐蚀能力。

众做周知,钝化会增强不锈钢的耐腐蚀能力,但是需要明白的是:使这些高科技的合金能发挥最好的性能,必须要兼顾制造、材料整体性能以及处理工艺各个方面。

根据MIL-STD-753硫酸铜测试,左边的是经过钝化的,邮编是没有钝化的。

参考文献:
1.ASTM A-380-96 不锈钢部件、设备以及系统的清理、除锈和钝化标准实施办法;
ASTM委员会A-1:关于钢、不锈钢和有关合金
ASTM标准
2.Fed. Spec. QQ-P-35C, 1988年10月28,耐蚀刚的钝化处理;
3.ASTM A-967-96 不锈钢零件化学钝化处理的标准规范;
4.ASTM B-117-95 盐雾试验一起的标准操作。

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