AMS 2649C中英文对照

RATIONALE
综述
This revision was issued to add requirements for examination of carburized surfaces and to remove requirements for (1) blasting or abrading to prepare the parts and (2) approval of the
anti-smut chemical. Other changes were deemed necessary as part of the SAE Five Year Review process.
这次改版增加了检查渗碳表面的要求，并去除了（1）喷砂或研磨零件的预处理要求以及（2）防污化学物的批准要求。

其他的变化是SAE五年评审程序的必要更改。

1. SCOPE
范围
1.1 Purpose
目的
This specification establishes the requirements for etch inspection of bare high-strength low-alloy steel parts having tensile strength of 180 ksi (1241 MPa) and higher and of carburized parts to detect overheating caused by abusive machining or grinding in the heat treated condition, and to detect localized discontinuous carburization. This process is not applicable to surface hardened steels produced by nitriding or carbonitriding. This process may remove 0.0001 to 0.0005 inch (2.5 to 12.7 micrometers) from the surface of the part.
本规范规定了拉伸强度不低于180 ksi（1241 MPa）的高强度低合金裸钢零件和渗碳零件的烧伤检查，以检查材料在热处理状态中加工和磨削不当造成的过热，以及局部不连续渗碳。

本工艺不适用于由氮化或氰化产生的表面硬化钢。

本处理过程可能去除零件表面0.0001- 0.0005英寸（2.5- 12.7微米）的厚度。

1.2 Classification
类型
Etchants used in this specification are classified as follows:
Type 1 - Nitric acid in water or alcohol with an anti-smut additive
Type 2 - Nitric acid in water or alcohol
Type 3 - Ammonium persulfate in water
本规范中使用的腐蚀剂分类如下：
第1类——水或酒精中加硝酸，并混合防污添加剂
第２类——水或酒精中加硝酸
第３类——水中加过硫酸铵
1.2.1 Type 1 and Type 2 etchants may be used interchangeably. Type 1 immersion or Type 3
swabbing method shall be used when the part cannot be hydrogen embrittlement relieved.
第1类和第2类腐蚀剂可以互换使用。

当零件无法去氢脆时，应该使用第1类浸泡法或第３类擦抹法。

1.2.2 Type 3 etchant shall be applied by swabbing and only used when authorized by the cognizant engineering organization.Type 3 is not as sensitive for detecting grinding burns as Type 1 or Type 2.
只有得到授权的工程组织批准后，才能使用第3类腐蚀剂擦抹的方法。

第３类腐蚀剂没有第1类和２类腐蚀剂检查磨削烧伤的灵敏度高。

1.3 Safety - Hazardous Materials
安全——危险物品
While the materials, methods, applications, and processes described or referenced in this specification may involve the use of hazardous materials, this specification does not address the hazards that may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved.
本规格中描述或引用的材料、方法、用途和工艺可能涉及到危险物品的使用，但本规范没有说明这些使用的危险性。

使用者自行负责熟悉安全和正确使用所有危险物品，并且采取必要的预防措施，确保所有有关人员的健康和安全。

The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The processor may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been cancelled and no superseding document has been specified, the last published issue of that document shall apply.
在订单之日现行有效的以下文件版本，在这里规定的范围内成为本规范的一部分。

除非规定使用某特定版本，操作者应根据文件后续修订版本进行操作。

若引用文件被取消且未规定替代规范，则应使用该规范的最新出版版本。

2.1 SAE Publications
SAE出版物：
Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), .
可联系以下方式获取：ASE, 400 Commonwealth Drive, Warrendale, PA 15096-00019（邮编），电话：877-606-7323 (美国和加拿大境内) 或者724-776-4970 (美国境外)或访问该网址。

A MS 2759/9 Hydrogen Embrittlement Relief (Baking) of Steel Parts
AMS 2759/9 钢制零件去氢脆（烘烤）
ARP1923 Qualification and Certification of Etch Inspectors
ARP1923 烧伤检验人员的评定和认证
2.2 U.S. Government Publications
政府出版物
Available from DODSSP, Subscription Services Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094 or .
可联系以下方式获取：DODSSP, Subscription Services Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094（邮编），或访问该网址。

MIL-PRF-16173 Corrosion Preventive Compound, Solvent Cutback, Cold-Application
MIL-PRF-16173 冷用溶剂稀释型防锈混合物
MIL-PRF-32033 Lubrication Oil, General Purpose, Preservative (Water-Displacing, Low Temperature)
MIL-PRF-32033 通用防锈润滑油（水驱，低温）
3. TECHNICAL REQUIREMENTS
技术要求
3.1 Preparation
准备
3.1.1 Parts to be etch inspected shall be cleaned to remove contaminants that will prevent wetting of the etching solution. The part to be etched shall have a water-break-free surface when held vertically for 30 seconds. Cleaned parts shall not be touched with bare hands prior to inspection. 待烧伤检查的零件应该清洁，除去会妨碍腐蚀溶液润湿零件的污染物。

将把待烧伤的零件竖直立放30秒，零件应该有一层水膜不破表面。

在检查之前，清洁的零件不应该直接用手接触。

3.1.2 Surface activation shall be performed as follows:
3.1.2表面活化应该按照如下步骤操作：
3.1.2.1 When blasting is performed, aluminum oxide or silicon carbide media shall be used to produce a matte appearance. Parts that can be damaged by blasting or may trap the blasting media shall not be cleaned by blasting.
进行喷砂时，应该使用氧化铝或金刚砂介质产生磨砂外观。

可能被喷砂损伤或可能吸附喷砂介质的零件不应该用喷砂清洁。

3.1.2.2 When sanding or abrading is performed, 180 grit or finer bonded abrasive shall be used to produce a matte appearance.
当进行喷砂研磨时，应该使用粒度180或更细的黏合研磨剂生成磨砂外观。

3.1.2.3 Alternative methods of surface activation may be used when acceptable to purchaser.
如果得到买方认可，可以使用表面活化的替代方法。

3.2 Solutions3.2溶液
3.2.1 Type 1 Etchant shall be a 3 to 5% by volume solution of 40° Be nitric acid in water or alcohol mixed with an antismut additive. The etch solution shall be maintained at ambient temperature.
第1类腐蚀剂应该是水或酒精中加3%-5%（按体积）的40°Be硝酸，再和防污添加剂混合。

腐蚀溶液应该保持在环境温度下。

3.2.1.1 The anti-smut additive shall be chemicals that, when mixed with the etchant, prevent the formation of smut on the surface of etched steel parts (See 8.3).
防污染添加剂应该是化学制品，它与腐蚀剂混合后，能防止烧伤的钢零件（见8.3）的表面上产生污物。

3.2.2 Type 2 Etchant shall be a 3 to 5% by volume solution of 40° Be nitric acid in water or alcohol. The solution shall be maintained at ambient temperature.
第２类腐蚀剂应该是水或酒精中加3%-5%（按体积）的40°Be硝酸。

溶液应该保持在环境温度下。

3.2.2.1 De-Smut shall be 4 to 6% by volume solution of 22° to 23° Be hydrochloric acid in alcohol or water. The solution shall be maintained at ambient temperature.
防污添加剂应该是酒精或水中加4%-6%（按体积）的22°- 23°Be盐酸。

溶液应该保持在环境温度
下。

3.2.3 Type 3 Etchant shall be a 10 ± 1% by weight solution of ammonium persulfate in water maintained at ambient temperature. The solution shall be applied within 72 hours of mixing. See 8.
4.
第3类腐蚀剂应该是环境温度下的水中加10±1%（按重量）的过硫酸铵溶液。

溶液应该在混合后72小时内使用。

见8.4。

3.2.4 Rinse Solution
冲洗液
3.2.
4.1 Sodium phosphate shall be an aqueous solution containing 0.5 to 1.0 ounce per gallon (3.7 to 7.5 g/L) of sodium phosphate.3.2.4.1. The solution shall be maintained at 60 to 180 °F (16 to
82 °C).
磷酸钠溶液应该是磷酸钠含量为0.5-1.0盎司/加仑(3.7 to 7.5 g/L)的水溶液。

溶液温度应该保持在60°F- 180°F ( 16°C- 82°C）。

3.2.
4.2 Sodium hydroxide shall be an aqueous solution containing 2 to 6% by weight sodium hydroxide.The solution shall be maintained at 60 to 120 °F (16 to 49 °C).
氢氧化钠溶液应该是氢氧化钠含量为2%- 6%（按重量）的水溶液。

溶液温度应该保持60°F- 120°
F（16°C- 49°C）。

3.3 Procedure3.3程序
3.3.1 General概要
3.3.1.1 Etch time for the solution shall be determined using a sample part of the same alloy with a known overheated condition and in the same heat treat condition as the production parts to be processed. Etch time shall be that time required to start turning the part a uniform gray, determined by personnel certified in accordance with 3.5.2.
应该使用与待烧伤零件相同合金（该合金的过热状态已知）和相同热处理条件的试样来确定溶液的
烧伤时间。

烧伤时间应是零件开始变为相同的灰色所需要的时间，由本规范3.5.2中规定的合格人员确定。

3.3.1.2 Etching shall be performed under the supervision of personnel certified in accordance with 3.5.2.
应该在本规范3.5.2中规定的合格人员的管理下进行烧伤操作。

3.3.1.3 All examinations shall be performed under a light of not less than 200 foot-candles (2153 lx) by personnel certified in accordance with 3.5.2.
所有检查都应由合格人员在不低于200英尺-烛光（2153勒克司）的灯光下操作。

3.3.1.4 Parts having areas that cannot be adequately etch inspected due to geometric restrictions shall be inspected by alternative methods or techniques that have been approved by the cognizant engineering organization.
由于几何形状限制、有些表面无法烧伤检查的零件，应使用授权工程组织批准的替代方法检查。

3.3.1.5 Parts shall be racked for immersion etching to prevent contact with each other and to ensure uniform etching on all surfaces that are to be inspected.
零件应该放在架上进行浸泡烧伤，防止零件互相接触，并且确保所有待检查表面烧伤均匀。

3.3.2 Type 1 Etch
第1类烧伤
3.3.2.1 Each part shall be immersed in etch solution conforming to 3.2.1 the time determined for the sample part.
每个零件应该浸泡于符合3.2.1的烧伤溶液中，浸泡时间由试样确定。

3.3.2.2 Without permitting any etched part to dry, each part shall be immediately rinsed in overflowing tap or hot (130 to 180 °F [55 to 82 °C]) water for not less than one minute. Parts shall be dried or immersed in waterdisplacing oil (MIL-PRF-32033) immediately.
烧伤后的所有零件不容许弄干，而应该立即在溢流自来水或热（130°F- 180°F [ 55°C- 82°C])水中冲洗至少一分钟。

零件应该立即弄干或在水驱油中浸泡（MIL-PRF-32033）。

3.3.2.3 Dried or oiled parts shall be visually examined.
弄干或或油封的零件应该目检。

3.3.3 Type 2 Etch
第２类烧伤
3.3.3.1 Each part shall be entirely immersed in etch solution conforming to 3.2.2 for the time determined for the sample part.
每个零件应该完全地浸泡于符合3.2.2的烧伤溶液中，浸泡时间由试样确定。

3.3.3.2 Without permitting etched parts to dry, parts shall be immediately rinsed in overflowing tap water for not less than one minute.
烧伤后的零件不容许弄干，应该立即在溢流自来水中处冲洗至少一分钟。

3.3.3.3 Each part shall be immersed in the de-smut solution conforming to 3.2.2.1 for 15 to 120 seconds.
每个零件应该浸泡于符合3.2.2.1的防污溶液中15至120秒。

3.3.3.4 Without permitting de-smutted parts to dry, parts shall be immediately rinsed in overflowing tap water for not less than one minute.
除去污物后的零件不容许弄干，应该立即在溢流自来水中冲洗至少一分钟。

3.3.3.5 Parts shall be rinsed with one of the solutions conforming to 3.2.4 for not less than one minute.
零件应该用符合3.2.4的一种溶液冲洗至少一分钟。

3.3.3.5.1 Parts that were immersed in the sodium hydroxide solution shall be rinsed, in tap or hot (130 to 180 °F [55 to 82 °C]) water, for not less than one minute. Parts shall be dried or immersed in water-displacing oil (MIL-PRF-32033) immediately.
浸泡于氢氧化钠溶液后的零件应该在自来水或热（130°F- 180°F [ 55°C- 82°C]）水中冲洗至少分钟。

零件应该立即弄干或在水驱油（MIL-PRF-32033）中浸泡。

3.3.3.5.2 Parts that were immersed in sodium phosphate solution do not require a water rinse but shall be dried or immersed in water-displacing oil (MIL-PRF-32033).
浸泡于磷酸钠溶液中的零件不要求水冲洗，但是应该弄干或在水驱油中浸泡（MIL-PRF-32033）。

3.3.3.6 Dried or oiled parts shall be visually examined.
弄干或油封的零件应用目检。

3.3.3.7 Hydrogen Embrittlement Relief
去氢脆
Parts that are desmutted with hydrochloric or other reducing acids shall be treated in accordance with AMS 2759/9. Such baking shall be performed prior to subjecting the parts to any stress or mechanical operations.
用盐酸或其他的还原酸去污的零件，应该按照AMS 2759/9处理。

应在零件接受任何应力或机械操作之前进行这种烘烤操作。

3.3.4 Type 3 Etch(See 1.2).
第３类腐蚀剂（见1.2）。

3.3.
4.1 Etch solution conforming to 3.1.3 shall be applied by swabbing or immersing for the time determined for the sample part.
零件应使用符合3.1.3的腐蚀溶液擦拭或浸泡，擦拭或浸泡的时间由试样确定。

3.3.
4.2 Parts shall be rinsed by swabbing with or immersing in clean water followed by swabbing with or immersing in alcohol. Parts shall be dried or immersed in water-displacing oil
(MIL-PRF-32033 or equivalent) immediately after rinsing.
零件应该用清水擦拭或浸泡清洗，接着用酒精擦拭或浸泡。

冲洗后，零件应该立即弄干或在水驱油（MIL-PRF-32033或标准）中浸泡。

3.3.
4.3 Dried or oiled parts shall be visually examined.
弄干或油封的零件应该进行目检。

3.3.
4.4 Hydrogen Embrittlement Relief
去氢脆
Parts that were immersed in etch solution shall be treated in accordance with AMS 2759/9 after
the parts are etched and prior to subjecting the parts to any stress or mechanical operations.
在烧伤之后并在接受任何应力或机械操作之前，浸泡于腐蚀溶液中的零件应该按照AMS 2759/9处理。

3.4 Visual Examination3.4
目检
Unless other acceptance standards are specified by the cognizant engineering organization, acceptance criteria shall be as follows:
除非授权的工程组织指定其他验收标准，应按照如下验收标准执行：
3.4.1 If no overheating or discontinuous carburization, as applicable, has occurred, the etched surface will be uniform light gray color over the entire area, and the part is acceptable.
如果没有出现过热或不连续渗碳（根据实际情况），烧伤表面的全部面积将是统一的浅灰色，则零
件是可接受的。

3.4.2 Overtempering
过度回火
Areas of parts etching darker, light brown to black, in relation to the surrounding areas have an indication of overtempering or localized carburization. Parts with this indication are not acceptable and shall be reinspected in accordance with 3.4.6.
与周围面积相比，零件有烧伤面积呈现暗灰色，浅棕色直到黑色，这指示表面过度回火或局部不连
续渗碳。

有这种指征的零件不可接受并且应该按照3.4.6重新检查。

3.4.3 Rehardening
再硬化
Areas of parts etching light gray to white surrounded by a light brown or black border have an indication of rehardening. Parts with this indication are not acceptable and shall be reinspected in
accordance with 3.4.6.
零件有烧伤面积呈现浅灰色直到白色，并有一圈浅棕色或黑色边缘，这指示零件再硬化。

有这种指征的零件不可接受并且应该按照3.4.6重新检查。

3.4.4 Extraneous Indications
外来的指征
Etched surfaces with fingerprints, spots, smeared metal, or any other extraneous indications after etching are not acceptable and shall be cleaned, re-etched, and reinspected in accordance with 3.4.6.
在烧伤之后，腐蚀表面有手印、斑点、切屑或任何其他外来的指征，则零件是不可接受的，并且应该清洁，重新烧伤，并且按照3.4.6重新检查。

3.4.5 Carburized Parts
渗碳零件
3.4.5.1 Absence of Carburization
没有渗碳
The absence of carburization in any local area where carburization is required (localized discontinuous carburization) is not acceptable and such parts shall be reinspected in accordance with 3.4.6
任何要求渗碳的局部面积没有渗碳（局部不连续渗碳），则零件不可接受，并且应按照3.4.6重新检查。

3.4.5.2 Unauthorized Carburization
不许可的渗碳
The presence of carburization in areas that are not specified are not acceptable and such parts shall be reinspected in accordance with 3.4.6.
未要求渗碳的面积却有渗碳层，这种零件不可接受，并且应按照3.4.6重新检查。

3.4.6 Reinspection
重新检验
Parts with areas indicating overtempering,rehardening, or absent or unauthorized carburize shall be cleaned in accordance with 3.1, re-etched in accordance with the applicable procedure in 3.3, and re-examined in accordance with 3.4 one time only. Recurrence of initial indications shall be cause for rejection.
零件有面积出现过度回火，再硬化，或没有渗碳或不许可的渗碳的指征，应该按照3.1清洁，按照适用程序重新烧伤并且按照3.4再度检查，这个过程只能重复一次。

再出现前面的指征应被拒收。

3.5 Qualification
评定
3.5.1 Solution Qualification
溶液评定
3.5.1.1 The etch solution shall be qualified daily or prior to use by etching a sample part with a known unacceptable condition such as from overheating, carburization, or decarburization.
烧伤溶液应每天评定，或者在每次使用前，使用已知不可接受条件（例如过热、渗碳、脱碳）的试样来评定溶液。

3.5.1.2 The etched part shall be examined to confirm that the unacceptable condition (3.5.1.1) can be detected with the solution and the selected etching time.
检查烧伤零件，以确认用溶液和选择的烧伤时间能够探测零件的不可接受条件（3.5.1.1）。

3.5.2 Inspector Qualification
检验员评定
All personnel performing etch inspection in accordance with this specification shall be trained and certified in accordance with ARP1923.
按照这个规范操作烧伤检查的所有人员应该按照ARP1923培训和评定。

4. QUALITY ASSURANCE PROVISIONS
质量保证规定
4.1 Responsibility for Inspection
检验责任
The inspection source shall be responsible for the performance of all required tests. Purchaser reserves the right to perform any confirmatory testing deemed necessary to ensure that etch inspection results conform to specified requirements.
检验机构应对所有要求的试验的效果负责任。

买方保留执行必要验证试验的权利，以保证烧伤检查结果符合指定要求。

4.2 Classification of Tests
试验的分类
4.2.1 Acceptance Tests
验收试验
Visual examination (3.4) shall be performed to determine product acceptance.
应该执行目检（3.4）以确定产品是否可接受。

4.2.2 Periodic Tests
定期试验
Tests to maintain the solutions (3.5.1) are periodic tests.
保持溶液（3.5.1）符合性的试验是定期试验。

4.3 Sampling and Testing
抽样和试验
Etch inspection shall be performed on all parts or as agreed upon by purchaser and processing .应该对所有零件或按照买方和检验机构商定的检查数量执行烧伤检查。

4.4 Reports
报告
The processor (inspection source) shall furnish with each shipment a report showing the type of inspection performed (see 1.2) and the results of the inspection. This report shall include the purchase order number, AMS 2649C, part number, and quantity.
检验人员（检验机构）应该随船提供一份报告，说明执行检查的类型（见1.2）和检查的结果。

这个报告应该包括订单编号、AMS 2649C、零件号和数量。

5. PREPARATION FOR DELIVERY
交货准备
5.1 Identification
标印
Parts that have been accepted by etch inspection described herein shall be identified as specified in 5.1.1 and 5.1.2.
按照本规范烧伤检查后接受的零件，应按照5.1.1和5.1.2进行标印。

5.1.1 The letters AE or NE (See 8.2) shall be legibly rubber-stamped on all parts or processing records, unless another method is specified.除非指定另外的方法，应在所有的零件或过程记录中清晰地用橡皮图章盖上字母AE或者NE(见8.2)。

5.1.2 The marking shall have no deleterious effect on the parts and shall be sufficiently stable to withstand normal handling.
标印应该对零件没有不利影响，并且应该足够稳定，能经受正常处理的影响。

5.2 Packaging
包装
5.2.1 Parts shall be protected from corrosion during subsequent storage, handling, and shipping, as applicable. Some acceptable methods include either coating with MIL-PRF-32033 or
MIL-PRF-16173 Grade 3 corrosion-preventive compound or packaging in commercial
volatile-corrosion-inhibiting wrapping.
零件应根据实际情况，为后续的贮存、处理和装船过程中的腐蚀提供防护。

可接受的方法包括，涂上MIL-PRF-32033或者MIL-PRF-16173三级防腐蚀剂，或者装在商用挥发性防腐包装中。

5.2.2 Inspected parts shall be handled and packaged to ensure the required physical characteristics are preserved.
检查过的零件应该处理和包装，以保持要求的物理特性。

5.2.3 Packages of inspected parts shall be prepared for shipment in accordance with commercial practice and in compliance with applicable rules and regulations pertaining to the handling, packaging, and transportation of the parts to ensure carrier acceptance and safe delivery.
检查结束后，零件装运准备应符合商业惯例和零件处理、包装和运输的有关适用规则和条例，以保证承运者被接受和安全交货。

6. ACKNOWLEDGMENT
确认
The processor shall mention this specification number and its revision letter in all quotations and when acknowledging purchase orders.
检验人员应该在所有的报价中并在确认订单时指出本规范编号及其版本编号。

7. REJECTIONS
拒收
Not applicable.
不适用。

8. NOTES
说明
8.1 A change bar (|) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of a specification.An (R) symbol to the left of the document title indicates a complete revision of the
specification, including technical revision.Change bars and (R) are not used in original publications, nor in specifications that contain editorial changes only.
位于左边空白的变更条（｜）用于方便使用者确定新版本对前一版本的技术性修正（不是编缉性修改）的位置。

在文件标题左方（R）的符号表示规范的所有修订，包括技术性修正。

变更条和（R）不适用原版，也不适用只包括编辑性修改的规范。

8.2 The process "etch inspection" may also be known by other terms, such as "temper etch", "acid etch" (AE) or "natal etch" (NE). These are all terms for the same inspection process for detection of rehardening or overtempered areas caused by abusive machining or grinding of steel parts.
工艺“烧伤检查”可能也使用其他的术语，例如“回火酸浸蚀检查”，“酸洗检查”（AE）或者"硝酸烧伤"（NE）。

这些术语都是指同一种检验过程，用于检测钢零件加工或者磨削不当造成的再硬化或者过度回火面积。

8.3 The anti-smut additive is a material that is stable when mixed with nitric acid, inhibits smutting from occurring on the surface of the part during nitric acid etching, has excellent wetting properties, does not evolve hydrogen during the etching operation, is noncombustible, is completely soluble in water, and does not evaporate from the etch solution.
防污添加剂是一种与硝酸混合后能够稳定的材料，能够防止零件表面在硝酸烧伤期间产生污染物，有很好的湿润性，在烧伤操作期间不产生氢，不可燃，可完全溶于水中，并且不会从烧伤溶液中蒸发。

8.4 Chemical Information8.
化学信息
After mixing with water, ammonium persulfate decomposes to form sulfuric acid, which will also etch but can produce hydrogen embrittlement. “Alcohol” as used herein refers to technical grade methanol or commercial denatured alcohol. “ Sodium Phosphate ” as used herein refers to tribasic sodium orthophoshate commonly known as sodium triphosphate, technical grade.
在和水混合之后，过硫酸铵分解产生硫酸，而硫酸也能烧伤零件，但会产生氢脆。

这里使用的“酒精”是指工业级甲醇或者商用变性洒精。

这里使用的“磷酸钠”是指三盐基的一代磷酸钠，通常称为工业级的三磷酸钠。

8.5 Application of oil to etched parts can enhance the contrast between acceptable and unacceptable areas.
将油用于烧伤零件可以增大可接受面积与不能接受面积之间的差别对比。

8.6 Terms used in AMS are clarified in ARP1917.
AMS使用的术语解释见ARP1917。

8.7 Dimensions and properties in inch/pound units and the Fahrenheit temperatures are primary; dimensions and properties in SI units and the Celsius temperatures are shown as the approximate equivalents of the primary units and are presented only for information.
尺寸和特性首选英寸/磅和华氏温度为单位；尺寸和特性以SI单位和摄氏温度是首选单位的近似等效值，仅用于参考。

8.8 Purchase documents should specify not less than the following:
AMS 2649C
Quantity of parts to be etched
Special packaging, if required.
采购文件应至少规定以下几项：
AMS 2649C
烧伤零件的数量
如果需要，特殊包装。

8.9 Similar Specifications
MIL-STD-867 is listed for information only and shall not be construed as an acceptable alternative unless all requirements of this AMS are met.
类似规范
MIL-STD-867仅供参考，除非满足本AMS规范的所有要求，MIL-STD-867不能作为本标准可接受的替代规范。

PREPARED BY AMS COMMITTEE “B” AND “AMEC”
由AMS委员会“B”小组和“AMEC”小组编制。