基于deform模具寿命的预测(中英文)

Abstract
摘要
This paper describes the estimation method of die service life based on wear and the plastic deformation of dies in hot forging processes. Die service life is considerably shortened due to the thermal softening of surface layer, caused by the high thermal load and long contact time between the dies and the deforming material. Also, the die service life depended on wear and the plastic deformation of dies can be to a large extent determined by finite element (FE) analysis, wear and thermal softening tests. These are some of the major limiting factors affects die accuracy and die service life, and forming velocity and initial die temperatures influence greatly wear and the plastic deformation of hot forging dies. In this study, two methods are suggested for estimating the service life of hot forging dies by plastic deformation and abrasive wear, and these applied to predict the product quantity according to two main process variables, forming velocity and initial die temperature for a spindle component. Through the applications of the suggested methods, the thermal softening of dies due to the local temperature rise led to the reduction of the service life of hot forging dies by plastic deformation more than by abrasive wear. © 2004 Elsevier B.V. All rights reserved.
本文介绍了计算方法的模具使用寿命基于磨损和塑性变形的模具在热锻过程。

模具使用寿命大大缩短由于热软化的表面层，高所造成的热负荷和长期接触死亡之间的时间和变形的材料。

此外，模具使用寿命取决于磨损和塑性变形的模具可在很大程度上取决于有限元（远东）分析，磨损和热软化试验。

这些都是一些主要限制因素影响模具的精度和模具使用寿命，并初步形成速度和模具温度的影响力大大磨损和塑性变形的热锻模。

在这项研究中，提出了两种方法估算的使用寿命热锻模的塑性变形和磨损，而这些用于预测产品数量根据两个主要过程变量，初步形成速度和模具温度为主轴的组成部分。

通过应用所建议的方法，热软化的死亡，由于当地气温上升导致减少使用寿命的热锻模的塑性变形超过了磨料磨损。

© 2004埃尔塞维尔湾五，保留所有权利
Keywords: Hot forging; Die service life; Wear; Plastic deformation; Thermal softening; Tempering parameter
关键词：热锻;模具使用寿命;磨损;塑性变形;热软化; 回火参数
1.Introduction
1. 前言
Hot forging is one of the most conventional metal-forming processes used in the production of critical parts in various industries [1]. Actually, it is widely used in the manufacturing of automobiles and industrial machine components. In particular, this process can be effectively used to form materials with the high flow stress. Die service life greatly influences manufacturing costs, productivity and product quality. During hot forging process, die service life is dramatically shortened by thermal cycle, excessive metal flow and a decrease in die hardness [2].
热锻是最传统的金属成形过程中所使用的关键部件生产中各行业[ 1 ] 。

其实，它广泛用于制造汽车和工业机械部件。

特别是，这一过程可以有效地利用，形成材料的高流动应力。

模具使用寿命大大影响了生产成本，提高生产率和产品质量。

在热锻过程中，模具的使用寿命大大缩短了热循环，过度金属流动和减少模具硬度[ 2 ] 。

Nowadays, manufacturing costs depend on how die service life can be extended for sound products without any kinds of internal and external defects during hot forging process. Subcontractors and suppliers are increasingly under pressure with regard to cost reduction and responsibility for the development of new components. These requirements are more critical in the
automotive industry. Therefore, it is important to improve the technical skills in the areas of material science and metallurgy as well as in the area of tool design.
如今，生产成本取决于模具的使用寿命可以延长产品的声音没有任何形式的内部和外部缺陷在热锻过程。

分包商和供应商正在受到越来越多的压力就减少成本和责任的发展，新的组成部分。

这些要求是更重要的汽车行业。

因此，重要的是要提高技术技能方面的材料科学和冶金以及在该地区的模具设计
The knowledge of computer aided design (CAD) and numerical simulation also becomes very helpful. In the forging industry, tooling costs can reach up to about 50% of a component cost. Therefore, it is obvious that the reduction of component costs requires an optimization of tools, in particular, an improvement in performance and service life [3]. During hot forging process, forging tools are not only subjected to mechanical stresses, but also to thermo mechanical stresses induced by the thermal cycling and successive forging operations.
知识的计算机辅助设计（ CAD ）和数值模拟也变得非常有帮助。

在锻造工业，加工费用可达约50 ％的元件成本。

因此，很显然，减少元件成本需要有一个优化的工具，特别是改善性能和使用寿命[ 3 ] 。

在热锻过程中，锻造工具不仅受到机械应力，而且还热机械应力引起的热循环和连续锻造业务。

Proper selection of the die material and of the die manufacturing technique determines, to a large extent, the useful life of forming dies. Dies may have to be replaced for a number of reasons, such as changes in dimensions due to wear or plastic deformation, deterioration of the surface finish, breakdown of lubrication, and cracking or breakage [4]. Many researchers have been investigated the influences of process conditions on die service life during metal forming process [5–7]. The surface hardness of a die decreases owing to the thermal softening of hot forging dies. This thermal softening effect accelerates tool failures [8]. The limiting factors of die service life can occur simultaneously or separately during hot forging process. Due to the different characteristics of processes or products, die service life can be decreased by wear or by the plastic deformation [9].
正确选择模具材料和模具制造技术决定，在很大程度上，使用寿命形成死亡。

模具可能要取代有许多原因，如变化方面，由于磨损或塑性变形，恶化的表面光洁度，细目润滑，打击或断裂[ 4 ] 。

许多研究人员进行调查的影响，工艺条件对模具使用寿命在金属成形过程[ 5-7 ] 。

表面硬度的死亡减少由于热软化热锻模。

这热软化效应加速工具失败[ 8 ] 。

的限制因素的模具使用寿命可同时或分别发生在热锻过程。

由于不同的特点，工序或产品，模具使用寿命可减少磨损或塑性变形[ 9 ] 。

This study developed two methods to estimate die service life in hot forging processes. One is a method that can predict the plastic deformation of a die and the other is to calculate the amount of die wear. These methods have been applied to evaluating the service life of a finisher die for the hot forging process of an automobile part, and the possible maximum production quantity which describes die service life will be evaluated according to the variations of initial die temperature and forming velocity.
本研究开发的两种方法来估计模具使用寿命在热锻过程。

其中一个方法，可以预测的塑性变形的模具和其他是计算的数额的模具磨损。

这些方法已应用于评价的使用寿命完美收官模热锻过程中汽车的一部分，可能最大的生产量描述模具使用寿命将评价根据变化的初步成形模具温度和速度。

2.Methods for estimating die service life
2.的方法来估计模具使用寿命
This study developed two methods for estimating the service life of dies in hot forging process.
One is a method that can predict the plastic deformation of the die; the other is for calculating
abrasive tool wear.
本研究开发的两种方法估算的使用寿命模具在热锻过程。

其中一个方法，可以预测的塑性变
形的模具;另一种是计算磨具的磨损。

Die service life based on plastic deformation
2.1模具使用寿命基于塑性变形
During the hot forging process, the temperature of a die increases due to the contact between
the dies and the hot deforming material. The rate of temperature rise can be attributed to several
factors, such as the initial temperature of dies and billet, the contact time and pressure, the die
material and surface treatment conditions. The thermal softening induced by this temperature rise
gradually reduces die hardness, and finally leads to the plastic deformation of a die [8].
The longer contact time at the elevated temperature gives rise to a decrease of the surface hardness
of a die. In order to consider the thermal softening effect in estimating die service life against
plastic deformation, it is required to introduce the tempering parameter, M , as shown in Eq. (1),
which represents the effect of die hardness change on the contact temperature and time successive
forging cycles [9]:
在热锻过程中，温度的增加而死亡之间的接触死亡和热变形的材料。

率的温度上升可以归因
于几个因素，如初始温度的模具和坯料，接触时间和压力，模具材料及表面处理条件。

热软
化诱导这一温度上升逐渐降低模具硬度，并最终导致的塑性变形的死亡[ 8 ] 。

较长的接触时间在高温引起减少了表面硬度的死亡。

为了考虑热软化效应估计死亡使用寿命
对塑性变形，这是需要引进回火参数，男，所显示的均衡器。

（ 1 ） ，这是影响模具硬
度变化对温度和时间接触连续锻造周期[ 9 ] ：
31010)log (-⨯+⨯=t C T M
where T is the tempering temperature (K), C is the material constant which has about 20 for
carbon steel, t is the tempering time. Also, from starting to deform until ejecting the forged part,
the temperatures of die surface change during one forging cycle, so the introduction of equivalent
temperature is required. The equivalent temperature, eq T , can be approximately expressed as
shown in Eq. (2):
其中T 是回火温度（ K ） ， C 是材料常数其中大约有20对碳钢， T 是锻炼时间。

另外，
从开始变形，直到弹出伪造的部分模具表面的温度变化1锻造周期，因此采用等效温度是
必需的。

相当于温度，可近似表示显示均衡器。

（ 2 ） ：
32min max T T T eq +=
Where max T , and min T are the highest and lowest temperatures during one forging cycle,
respectively. 在那里，并且是最高和最低气温在1锻造周期分别。

To estimate die service life for the plastic deformation of a die induced by thermal softening,
the tempering time, t , at Eq. (1) is replaced with hardness holding time t h, where t h is the time
which takes until initial die hardness gradually reduces to reach the critical hardness by thermal
softening, as shown in Eq. (3):
估计模具使用寿命的塑性变形的热诱导死亡软化，回火时间，吨，在均衡器。

（ 1 ）改
为硬度日举行的时间，在那里次的时间，考虑到初始模硬度逐渐降低，达到临界硬度的热软
化所示，均衡器。

（ 3 ） ：
)1000exp(
C T M t eq yield h -⨯= where yield M is the M value when initial die hardness is equals to the corresponding hardness of
the yield strength of the die.
哪里是M 值时，最初的模具硬度等于相应的硬度屈服强度模具。

When the material is a perfect plastic, the hardness (HrC) of material is about three times of the
yield strength of material [10]. The main tempering curves of this hot work die material, H13,
obtained from thermal softening experiments is shown in Fig. 1.An actual working finishing die
was quenched at 1030 ◦C, and then it had the first tempering for 3 h at 550 ◦C and the second
tempering for 3.5 h at 600 ◦C. Die surface was treated as ion-nitriding process for 14 h at 520 ◦C.
当材料是一个完美的塑料，硬度（硬度）的材料是3倍左右的屈服强度的材料[ 10 ] 。

主要回火曲线这个热作模具材料， H13的，从热软化实验显示图。

1.An 实际工作完成淬
火模具是在1030年◦ C ，然后它的第一个锻炼的3小时在550 ◦ C 和第二回火为3.5 h
在600 ◦角模具表面被视为离子渗氮过程的14 h 在520 ◦角
Fig. 1. Main tempering curves of H13.
主要回火曲线H13的
Therefore, for hardness holding time for estimating the die service life considers the first and
second tempering time, which can be derived as follows:
因此，硬度保温时间估计模具使用寿命认为，第一次和第二次锻炼的时间，可以得出如下：
{}32110)log(-⨯+++=t t t C T M
h eq yield
21)1000exp(t t C T M t eq yield h ---⨯= Where,
⎭
⎬⎫⎩⎨⎧-+⨯=C t C T T t h eq )log (exp 1011
⎭
⎬⎫⎩⎨⎧-+⨯=C t C T T t h eq )log (exp 1021
where T 1, T 2 are the first and second tempering temperatures, t 1, t 2 are the hardness holding times
at the first and the second M yield values for T eq, respectively.
那里的T1 ，时刻是第一次和第二次回火温度， T1讯号，氚的硬度举行次在第一次和第二
次Myield 价值的毒性当量分别。

In order to calculate the hardness holding time, effective stresses and equivalent temperatures
can be obtained from rigid-plastic finite element analysis. M yield value can be determined from
the main tempering curve. t 1 and t 2 are substituted into Eq. (4) to obtain the hardness holding
time.
Finally, the die service life of the finishing die is calculated by dividing the hardness holding time
by one forging cycle time, and the die service life is expressed as the possible maximum
production quantity. The outline of a method for estimating die service life affected by plastic
deformation is shown in Fig. 2
为了计算硬度持有时间，有效应力和等效温度可从刚塑性有限元分析。

Myield 价值来确
定的主要回火曲线。

T1和T2是代入方程。

（ 4 ） ，以获取硬度保温时间。

最后，模具使用寿命整理模具除以硬度保温时间由一个锻造循环时间，及模具使用寿命表示
可能最高产量。

大纲的估算方法模具使用寿命的影响塑性变形图所示。

2
Fig. 2. Flow chart for plastic deformation analysis.
流程图塑性变形分析
Fig. 3. Flow chart for abrasive wear analysis.
流程图磨损分析
Die service life based on abrasive wear
2.2 。

模具使用寿命基于磨粒磨损
Abrasive wear is defined as the intentional removal of materials from a surface, as in grinding and polishing of engineering components, and the unwanted loss of material that occurs when machine components are in relative motion [11]. In hot forming, the die steel should have a high hot hardness and should retain this hardness over extended periods of exposure to elevated temperatures. The factors affecting abrasive wear during metal contacts are temperature the roughness of contacting surfaces, the hardness of die material, the normal pressure on die surface, the sliding distance between contacting metals, and lubrication conditions, etc. The abrasive wear of dies influences dimensional accuracy and the surface finish of products during hot forging processes [12,13].
磨粒磨损是指故意去除材料表面，如在研磨和抛光的工程组成部分和有害物质损失时发生机械部件的相对运动[ 11 ] 。

在热成型，模具钢应具有较高的高温硬度和应保留这项硬度长时间暴露于高温下。

影响因素磨损金属的接触过程中的温度与表面粗糙度，硬度模具材料，正常的压力，模具表面，滑动之间的距离接触金属，润滑条件等磨损模具尺寸精度的影响和表面光洁度的产品在热锻过程[ 12,13 ] 。

Fig. 4. Shape and dimensions of a product and finishing die.
形状和尺寸的产品和整理死亡
Fig. 5. Process design of a spindle product.
工艺设计主轴的产品
In this study, in order to predict the wear profile of a die in metal forming processes, Archard wear
model is applied as shown in Eq. (5) [14]:
在这项研究中，为了预测磨损剖面的死在金属成形过程，查德磨损模型应用于所示，均衡器。

（ 5 ） [ 14 ] ：
h kPl
V 3
where V is the wear depth, k is the wear coefficient, P is the normal pressure on die surface, l is
the sliding distance and h is the surface hardness of the die.
其中V 是磨损深度， K 的磨损系数， P 是正常的压力，模具表面， L 是滑动距离和H 是表面
硬度模具
To estimate the die service life based on abrasive wear, it is needed to consider the hardness
change at high temperature of a die and the wear amount increase of surface layer with regard to
the contact time and temperature. A numerical model of abrasive wear as shown in Eq. (6), is
developed by considering the hardness change of a die toward the direction of wear depth.
估计模具使用寿命基于磨粒磨损，这是需要考虑的硬度变化在高温下的死和磨损量增加了表
层关于接触时间和温度。

数值模型磨损所显示的均衡器。

（ 6 ） ，是发达国家的考虑硬
度变化裸片方向的磨损深度。

∑=∆=N i s n t weardepth M h k
W 1)(),(3υσ
Table 1
Process conditions of FE analysis 工艺条件的有限元分析
Billet 坯料
Material 材料 AISI 1045
Thermal conductivity (N/s ◦C) 导热系数 74.93
Emissivity 发射率 0.3
Heat capacity ( N/mm ◦C) 热容量 3.602
Die
Material H 13
Thermal conductivity (N/s ◦C) 28.6
Emissivity 0.3
Heat capacity (N/mm ◦C) 3.574
Surface treatment Ion-nitride 表面处理离子氮化
Forging conditions 锻造条件
Friction factor (m) 摩擦系数 0.3
Heat transfer coefficient (N/smm ◦C) 传热系数 11.3
Convection coefficient (N/smm ◦C) 对流系数 0.02
Initial Billet/die temperature (◦C) 初始坯/模具温度 1200/200
Forging velocity (mm/s) 锻造速度 250
———————————————————————————————————————
————————————
Table 2
Variation conditions of process variables 条件的变化过程变量
Process variables 过程变量
Initial die temperature (◦C) 最初的模具温度 200
300
400
Forging velocity (mm/s) 锻造速度 200
250 300
The normal pressure (σn), the sliding velocity (v s), and the temperature distributions on die
surface are calculated from the rigid-plastic FE analysis, and the permitted amount of abrasive
wear and the critical value of surface hardness were obtained from wear test and thermal softening
experiments.
常压（σn ），在滑动速度（比），温度分布对模具表面的计算从刚塑性有限元分析，并允许磨损量和临界值的表面硬度得到了磨损试验和热软化实验
The amount of abrasive wear at each point on the die surface for one forging cycle was calculated through the wear analysis of Eq. (6), and then compared with the permitted value. Also, the hardness at the worn surface that resulted from this amount of abrasive wear was compared with the critical value. If the amount of abrasive wear is smaller than the permitted value, and the hardness at worn die surface is still greater than the critical value, then abrasive wear analysis will repeat until the integrated amount of abrasive wear reaches the permitted value. Finally, the production quantity which expresses die service life was determined from the total number of wear analysis. The flowchart of a method for estimating the die service life based on abrasive wear is shown in Fig. 3.
数额磨损各点的模具表面形成一个周期，通过计算磨损分析均衡器。

（ 6 ），然后与允许值。

此外，硬度在磨损表面造成这一数额的磨损比较的临界值。

如果磨损量小于允许值，硬度在破旧模具表面仍然大于临界值，然后磨粒磨损分析会重复，直至综合磨损量达到了允许值。

最后，生产数量表达模具使用寿命决心从总人数的磨损分析。

流程图的估算方法模具使用寿命基于磨粒磨损图所示。

3 。

3. Analyses and result 分析及结果
Fig. 4 shows a hot forging product to be analyzed based on plastic deformation and abrasive wear. One of automobile components, spindle part, is manufactured in three stages composed of upsetting and two forward/backward hot-forging operations. Fig. 5 shows the process design result for the hot forming of spindle part.
图。

4显示热锻产品的基础上分析塑性变形和磨损。

一个汽车零部件，主轴的一部分，是生产的三个阶段组成的破坏和两个向前/向后热锻行动。

图。

5显示了工艺设计结果的热成形主轴的一部分。

Fig. 6. Damage factor of a final product. 损伤因子的最终产品
Fig. 7. Temperature distributions for the initial die temperature.
温度分布的初始模具温度
This product has the height of 320 mm, maximum diameter of 131mm and a long extruded part. This discrete part requires a minimum machining and high dimensional accuracy. Unfortunately, abrasive wear or plastic deformation of the die occurred at the stepped corners as shown as point 1, 2 in Fig. 4, the die service life of this part depends on the change of the initial shape and dimension of these stepped corners during hot forging. The forming analysis conditions and the variations of process variables for estimating die service life are listed in Tables 1 and 2, respectively. The distributions of damage value at final stage obtained from the FE analysis is shown in Fig. 6, these values appeared highly at two stepped corners. The damage factor can be used to predict fracture in forming operations [15,16].
该产品具有高度为320毫米，最大直径一三一毫米和长期挤压一部分。

这离散部分最少需要加工和高尺寸精度。

不幸的是，磨损或塑性变形模具发生在加紧角落显示为第1点， 2图。

4 ，模具的使用寿命取决于这一部分的变化，初步形成和加强这些方面的角落在热锻。

分析条件的形成和变化的过程变量估计模具使用寿命列于表1和表2分别。

分布损坏价值最后阶段获得的有限元分析显示图。

6 ，这些价值观念出现高度在两个加强角落。

损害因素可以用来预测骨折的形成行动[ 15,16 ] 。

Fig. 8. Nodal force and velocity distributions for the initial die temperature.
交点力量和速度分布的初始模具温度。

Therefore, the damage degree of these corners may directly relate to die service life. When the initial die temperature is low, it may influence product quality. When the initial die temperature is high, die hardness decreases. When the forming velocity becomes faster, the contact time between the hot deforming material and the dies is shortened and the equivalent temperatures become low. The initial die temperature control and selection of deformation velocity are very important to the die life.
因此，一定程度的损害这些弯道可能直接关系到模具的使用寿命。

当最初的模具温度很低，这可能会影响产品质量。

当最初的模具温度高，模具的硬度降低。

当形成速度变得更快，接触之间的时间热变形材料和模具缩短和相当于温度低。

最初的模具温度控制和选择的变形速度是非常重要的模具寿命。

Fig. 9. Effective stress and wear depth for initial die temperature.
有效应力及磨损深度初步模具温度
3.1. Influence of the initial die temperature影响的初步模具温度
In metal forming process, both plastic deformation and friction contribute to the heat generation. The temperatures developed in the process influence lubrication conditions, tool life, the properties of the final product, and the rate of production [4]. Above all, when the initial die temperature is high, the temperature difference between inside and outside of a billet becomes small, and this small temperature difference assists the sound metal flow. On the other hand, a high surface temperature may reduce die service life. But the low temperature of die surface can disturb metal flow and cause the surface defects.
在金属塑性成形过程中，塑性变形和摩擦有助于热量的产生。

温度发达国家在这一进程中的影响力润滑条件下，刀具寿命，性能的最终产品，以及为生产[ 4 ] 。

最重要的是，当最
初的模具温度高，温差内外成为一个小方坯，这小温差助攻金属流动的声音。

另一方面，较高的表面温度可降低模具的使用寿命。

但如此低的温度，模具表面可能干扰金属流动，造成表面缺陷。

As can be seen in Fig. 7, the temperature on die surface at two stepped corners (point 1, 2) increase differently, due to initial die temperature effect, for the same forging process. For the initial die temperature 400 ◦C at point 1, the die temperature is initially higher, but the maximum temperature is lower than for either 200 or 300 ◦C. Also, these results clearly indicate that the temperature gradient for the initial die temperature 400 ◦C is very large at point 2. The distributions of nodal force and velocity are shown in Fig. 8. It can be seen that nodal force acting on die surface decreases as the initial die temperature increases, whereas velocity of the workpiece at the vicinity of the die/material interface increases as the initial die temperature increases. The reason for this is that the metal flow increase with increasing temperature. The results of abrasive wear and stress analysis of finisher die are shown in Fig. 9, when initial die temperature is 400 ◦C, the wear depth (δ) at point 2 is approximate 1.898 mm, and is about four times of that at 200 ◦C. This is not surprising because the relative velocity between die and workpiece at point 2 for initial die temperature 400 ◦C is higher than for either 200 or 300 ◦C. Moreover, as initial die temperature increases, the hardness of the steel near the surface of the die decreases.
可以看出，在图。

7 ，温度对模具表面的两个加强角落（点1 ， 2 ）增加不同，由于最初的模具温度的影响，对同一锻造工艺。

在初期的模具温度400 ◦ C的第1点，模具的温度较高的初期，但最高温度低于200或300要么◦角另外，这些结果清楚地表明，温度梯度的初始模具温度400 ◦ C是非常大的第2点。

节点的分布是力量和速度显示图。

8 。

可以看出，节点力模具表面跌幅为初始模具温度升高，而速度的工件在附近的模具/材料界面增加，因为最初的模具温度上升。

这样做的理由是，金属流动增加随着温度的升高。

结果磨粒磨损和应力分析整理死于中显示图。

9 ，当最初的模具温度为400 ◦ C时，磨损深度（δ ）在第2点是近似一点八九八毫米，是大约4倍，在200 ◦角这并不奇怪，因为相对速度和工件之间的模具第2点的初步模具温度400 ◦ C是高于或者200或300 ◦角此外，由于最初的模具温度升高，硬度钢表面附近的死亡减少。

Fig. 10. Temperature distributions for forming velocity.
温度分布的形成速度
The results of the die service life estimation according to initial die temperatures for plastic deformation and abrasive wear are summarized in Tables 3 and 4, respectively. As the initial die temperature increases, the production quantity decreases. The possible maximum production quantity affected by abrasive wear is higher than that by the plastic deformation of a die. Generally, the yield strength of steels decrease at higher temperatures and yield strength is also dependent on prior heat treatment. The high initial die temperature causes the reduction of die hardness by thermal softening. The higher the initial hardness, the greater the yield strengths at various temperatures. From the results, die life resulting from plastic deformation of die is more important than from abrasive wear in terms of initial die temperature.
结果模具使用寿命据初步估计模具温度，塑性变形和磨损总结表3和表4分别。

作为最初的模具温度的增加，产量下降。

可能最大的生产量受磨损高于的塑性变形的模具。

一般来说，屈服强度钢减少，随着气温的升高，屈服强度还依赖于事先热处理。

在最初的模具温度高的原因，减少模具硬度的热软化。

较高的初始硬度，产量较大的优势在不同温度下。

从结果中，模具寿命产生塑性变形的死亡更重要的是从磨损方面初步模具温度。

Fig. 11. Nodal force and velocity distributions for forming velocity.
交点力量和速度分布形成速度
3.2. Influence of the forming velocity影响成形速度
When the deformation velocity becomes fast, forming cycle time is shortened, whereas the deformation load between the dies and the workpiece increases. As can be seen in Fig. 10 , the temperature on die surface at two stepped corners (point 1, 2) increase differently, due to forming velocity effect, for the same forging process. For the forming velocity 250 mm/sec, the die temperature increases gradually, but the maximum temperature is higher than for 300 mm/sec. Also, temperature gradient for the forming velocity 300 mm/s is large at point 2.
当变形速度变得快，形成循环时间缩短，而变形力之间的模具和工件增加。

可以看出，在图。

10 ，温度对模具表面的两个加强角落（点1 ， 2 ）增加不同，由于形成速度的影响，对同一锻造工艺。

形成速度为250毫米/秒，模具的温度逐渐增加，但最高温度高于300毫米/秒。

此外，温度梯度的形成速度为300毫米/秒的大第2点。

Fig. 12. Effective stress and abrasive wear depth for forming velocity.
有效的压力和磨损深度成形速度
The distributions of nodal force and velocity are shown in Fig. 11. It can be seen that nodal force acting on die surface decreases as the forming velocity increases, whereas velocity of the workpiece at the vicinity of the die/material interface increases as the initial die temperature
increases. The reason for this is that the metal flow increase with increasing forming velocity. The results of abrasive wear and stress analysis of finisher die are shown in Fig. 12, when forming velocity is 300 mm/s, the wear depth (δ) at point 2 is approximate1.261 mm, and is about three times of that at 200 mm/s.
节点的分布是力量和速度显示图。

11 。

可以看出，节点力下降的模具表面形成的速度增加，而速度的工件在附近的模具/材料界面增加，因为最初的模具温度上升。

这样做的理由是，金属流动的增加而日益成形速度。

结果磨粒磨损和应力分析整理死于中显示图。

12 ，当形成速度是300毫米/ s时，磨损深度（δ ）在第2点是approximate1.261毫米，约为3倍，在200毫米/秒
When the forming velocity increases, the die service life evaluated by the plastic deformation becomes longer. But its life by abrasive wear is relatively short. The estimation results of die service life according to forming velocity are shown in Tables 5 and 6, respectively. When the forming velocity is 200 mm/s, the plastic deformation of a die occurred early at the stepped corners (point 1, 2) owing to the local high temperature caused by the long contact time. As the forming velocity increases, the die service life based on plastic deformation was improved by the low local temperature through the short contact time at the stepped corners. When the forming velocity increased, the die service life based on abrasive wear decreased. From the results, die life resulting from abrasive wear of die is more important than from plastic deformation in terms of forming velocity.
当形成速度增加，模具使用寿命评价塑性变形变得更长。

但它的生命磨损是相对较短。

估算结果模具使用寿命根据成型速度显示表5和表6分别。

当形成速度是200毫米/ s时，塑性变形的死亡发生在年初加紧角落（点1 ， 2 ）由于当地的高温所造成的长期的接触时间。

由于形成的速度增加，模具使用寿命塑性变形的基础上进行了改进的地方温度低的短接触时间在加强角落。

当形成速度增加，模具使用寿命的基础上减少磨损。

从结果中，模具寿命磨损造成的死亡更重要的是从塑性变形方面形成速度
4. Conclusions结论
In this study, two methods for estimating the service life of hot forging dies by plastic deformation and abrasive wear are suggested, and these applied to predict the product quantity, according to two main process variables, forming velocity and initial die temperature. Through the applications of the suggested methods, the following conclusions were obtained.
在这项研究中，两种方法估算的使用寿命热锻模的塑性变形和磨损的建议，这些适用于预测的产品质量，根据两个主要过程变量，初步形成速度和模具温度。

通过应用所建议的方法，得到了以下结论。

1) The thermal softening of dies due to the local temperature rise led to the reduction of the service life of hot forging dies by plastic deformation more than by abrasive wear. When the forming velocity increased, the die service life caused by abrasive wear decreased.
1 ）热软化模具由于当地气温上升导致减少使用寿命的热锻模的塑性变形超过了磨料磨损。

当形成速度增加，模具使用寿命造成的磨损减少。

2) When the initial die temperature increased, the die service life by both plastic deformation and abrasive wear decreased, especially, the plastic deformation appeared to be the major limiting factor for die service life.
2 ）当最初的模具温度增加，模具使用寿命由塑性变形和磨损降低，特别是塑性变形似乎是主要限制因素模具使用寿命。

3) When the forming velocity increased, the die service life caused by plastic deformation was。