福特模具表面淬火要求.

1、一、Flame Hardening火焰表面淬火概述Flame hardening has been utilized for many years to harden a wide variety of tools dies, molds, machine parts, and fixtures. There are many advantages to the flame hardening process. Some of these advantages are hardening in selective locations, varying the levels of hardnes

2、s, speed of the process, low equipment costs and/or the hardening dies and die components that are too large to heat treat in existing furnace equipment.火焰淬火一直被用于强化各种工具、模具、铸模、机器零件、夹具。火焰硬化过程有很多优点，这些优势是硬化地点，硬化级别，速度具有可选择性，设备成本低廉，在现有的熔炉设备上不能对过大的硬化模具和部件进行热处理(flame surface quenching with acetylene and oxy

3、gen mixture combustion flame sprayed to the surface of parts, the parts quickly heated to quenching temperature, and then air cooling or water spray to the workpiece surface immediately, flame surface quenching is suitable for single piece or small batch production, hard and wear-resistant surface r

4、equirement, and can withstand the impact load of large medium carbon steel and medium carbon alloy steel parts, moulding surface covering parts such as convex R Angle and ridge, and trimming contour and rummaged through plastic profile, etc.)（火焰表面淬火是用乙炔和氧气混合燃烧的火焰喷射到零件表面，使零件迅速加热到淬火温度，然后空冷或立即用水向零件表面喷射

5、, 火焰表面淬火适用于单件或小批生产、表面要求硬而耐磨，并能承受冲击载荷的大型中碳钢和中碳合金钢件，如覆盖件模具型面凸R角和棱线部位，以及修边轮廓和翻遍整形型面等）Advantages:火焰表面淬火的优势如下：1. Low equipment cost compared to conventional furnace heat treating2. Selectively harden particular sections of a die or tooling insert3. Process mobility, die components to be hardened on line4

6、. Fast low cost processing by comparison to furnace hardening5. Large parts can be hardened with minimal distortion6. Parts too large to be furnace hardened can be hardened1. 和传统熔炉热处理相比设备成本较低2. 模具或零部件选择性的硬化区域3. 工艺的流动性，线上需要硬化的模具组件4. 更快更便宜5. 大的件可以在最小变形的情况下硬化6.无法使用熔炉硬化的大的件可以进行火焰硬化Concerns:火焰表面淬火关注点事项1.

7、 Operator skill, experience and dedication2. Cracking and distortion of the workpiece3. Shallow, low, nonuniform hardness penetration (case depth)4. Inadequate equipment and/or a poor working environment5. Overhardening, grain coarsening and melting and cracking of stress raisers (sharp corners, sha

8、rp edges, section changes, thin wall sections, weld areas.6. Decarburization and scaling7. Part distortion from nonuniform stress development1. 操作人员的技术，经验和对工作的投入2. 工件的开裂和变形3. 淬火层的深浅，不均匀的硬化渗透（深度）4. 设备不足，工作环境差5. 过硬化，晶粒粗化，应力集中处的融化和开裂（锐角，尖角，部分变化，薄的侧壁部分，焊接区域）6.脱碳和剥落7. 产生应力不均匀导致的鈑件变形A good example, of the

9、 advantages of flame hardening as opposed to conventional furnace hardening are automotive stamping draw dies. These large dies are frequently too large and heavy to furnace treat, quench and temper. They may also have a large percentage of area does not need to be hardened. Flame hardening can sele

10、ctively harden specific areas i.e., radii, character lines, and other high wear areas rapidly and conveniently.火焰淬火的优势包括自动冲压拉延模。这些模具过大不便使用熔炉加热，淬火和回火，可能有的地方是不需要硬化的，火焰硬化可以就淬火部分对需要淬火的区域具备选择性，如R角，特征线以及高磨损的地方The process of flame hardening has not changed significantly since the early 1900s.A combustible

11、gas flame usually Oxygen and Acetylene, is used to heat the surface a ferrous metal. The cast irons, cast steels and wrought tool steels may all be hardened via the flame technique. The procedure for flame hardening is performed by a hardening specialist who directs a hot torch flame onto the workpi

12、ece until the area to be hardened is heated to a suitable hardening (austenitizing) temperature usually a cherry red(1500/1700F). The surface hardness that develops on a given material can be controlled by varying the heating rate, hardening temperature, and by employing different quenching techniqu

13、es (water, polymer, forced air, still air, etc.).硬化工艺自1900年以来没有什么大的变化。可燃气体一般是氧气和乙炔，通常用于加热含铁金属表面。铸铁，铸钢和锻造工具钢也可以使用火焰方法。火焰硬化的过程通常是由专业人员操作，加热工件直到硬化区域达到适当的奥式温度，通常是樱桃红。在给定的材料上进行表面硬化处理，可以通过变换热率，硬化温度，以及使用不同的淬火手段（水，高分子聚合物，加压气流，蒸馏气体等）The end result of the austenitizing and rapid quenching is a hard martensiti

14、c case over top of a softer, more ductile inner core. Case depths (hardness penetration) will vary from 1/32 to 1/2 depending on the heat induced, the carbon content, the hardenability of the workplace material and the speed of the quench that follows the hot flame. To minimize concerns relating to

15、distortion, size change and brittleness, itis usually recommended that the workpiece be stress relieved after quenching from the hardening temperature奥氏体化和快速淬火的最终结果是在较软的，延展性更好的内心形成一个马氏体。硬化层深度范围为1/32 to 1/2？，取决于感应热度，碳含量，工件材质的硬化能力，以及淬火速度。为了最小化变形，变小，脆性，建议在硬化温度淬火后解除工件应力The flame hardening of automotive

16、stamping tool and dies as a process is often referred to as being more art than science. This is because quality results are very operator dependent. The person actually performing the flame-hardening operation is one of the most important, if not the most important factor in the entire process. The

17、 flame- hardener should be given the benefit of the best training, education, equipment and work space possible. A flame-hardening area could be established and maintained ata fraction of the investment in an average heat treating department. Consistent, satisfactory results can only be obtained if

18、the proper equipment and facilities are combined with the knowledge and skill that a dedicated, experienced flame hardening operator can provide.自动冲压模具的火焰淬火作为一种工艺，其质量结果大多取决于操作人员。实施火焰淬火的人员是最重要的因素之一。需要接受很好的培训，学习。火焰淬火的地点可以设在一个热处理的地方。要达到良好的满意的淬火的效果，要具备合适的设备，以及经验丰富，勤勉的工作人员。Plain carbon and medium-alloy s

19、teels (1060, 1090, 4140, 4150, 6150, etc.) are best suited for flame hardening. While there is an interest in the flame hardening of some higher -alloyed materials such as tool steels (S7, A2, D2, etc.), it must be kept in mind that these steels require more particular attention to the development a

20、nd maintainance of proper austenitizing temperatures, soak times, etc., due to their relatively high degree of hardenability. 纯碳和介质合金钢(1060、1090、4140、4150、6150、等)最适合火焰淬火。虽然火焰淬火合金的材料如工具钢(S7、A2,D2等)也比较有兴趣，一定要记住这些钢在开发和维护适当的奥氏体化温度、浸泡时间,等等,由于其相对高度的淬透性。NOTE: There is no substitute for taking the time to i

21、nspect and plan the flame hardening operation. The benefits of stress relieving, preheating before and tempering after flame hardening, become more critical as the design configuration of the work piece becomes increasing complicated, as the amount of cold work stresses in the work piece increase, a

22、nd as the hardenability of the steel being flame hardened increases. Complicated part designs include configurations with stress raisers (sharp corners, dramatic changes in cross-section, thick sections adjacent to thin sections, numerous holes, thin wall sections, large, massive and/or long thin se

23、ctions, etc.注意点：检查和计划火焰淬火的运作是无可取代的工作。随着工件设计的复杂性越来越大，之前的应力解除，预加热和淬火后的回火越来越重要。随着工件冷加工压力增大，火焰淬火的工件淬硬性增大。复杂的鈑件设计包括？（尖角，横截面的急剧变化，靠近薄的区域的厚的部分，很多孔，薄壁，大的，厚重的或长的薄的部分，等。）GENERAL COMMENTS一般注释 Insufficient Heating: Failure to heat the work piece to the critical temperature or to maintain the proper heat tempera

24、ture long enough will result in shallow and low hardness. This problem can be redressed by re-flame hardening to develop sufficient hardness.不充分热处理：没有将工件加热到位或没有持续足够的时间会导致硬性不足。这个问题要通过重新火焰淬火才能达到足够的硬性。Overheating: Application of too much heat may result in incipient (the beginning of melting of the mat

25、erials surface. This incipient melting may not be visible with the naked eye, but can be seen if a sample of the melted material is polished and viewed under a microscope at high magnification. Incipient melting damages the steel to the extent that it becomes very brittle and will crack under applic

26、ation of service load. This is especially true in work pieces with sharp section changes and/or design configurations with tight radii, sharp corners, thin-walled hole sections, etc. Material damaged by incipient melting cannot be repaired or reclaimed, and must be scrapped.过热：过热会导致材料的表面融化。也许刚开始的融化迹

27、象是肉眼无法看出来的，但是在高倍显微镜下可以看出打磨后的材料是有融化的。这会导致钢在某种程度上易碎，在装载时会开裂。特别是含有锐角，紧凑的R角，尖角，薄壁孔部分，等。初融导致的材料损伤无法修复，必须报废。Gas Type: Oxyacetylene is commonly used with a 1:1 mixture although other gas types are available. The oxyacetylene flame temperature is approximately 5590 F.气体形式：通常使用氧乙炔进行1:1的混合使用。火焰温度大约为5590 F。Fla

28、me Type: Use a neutral to a slightly carburizing flame. Generally a neutral flame type is best. Flame hardening experts favor a slightly carburizing flame in order to avoid the possibility of decarburizing the surface layer of the work piece. This can be accomplished by giving the outer flame tip a

29、very slight feather. 火焰类型：在轻微碳化的火焰上使用一个？中性火焰最佳。火焰淬火专家比较喜欢使用轻微碳化的火焰以避免工件表面层脱碳的可能性。？Quenching: Always water, oil, or air quench according to the recommendations of the steel manufacturer. Polymer quenches are available; these are slower than oil and faster than air quenching and, as a result, produce

30、lower levels of residual stresses. For air-hardening steels, however, a forced or still air quench is recommended whenever possible to keep stress development to an absolute minimum. Forced-air quenching can be performed by using a fan or compressor nozzle to pass cool air across the work piece afte

31、r it has been properly heated.淬火：根据钢板制造商的建议，一般是水，油或空气淬火。可以使用高聚合物淬火；比油淬火慢，比空气的快。结果就是残余应力低。对于空气硬化的钢板，建议尽可能的使用强迫或静止空气淬火以达到应力最小值。可以使用风扇或压缩机喷嘴在钣料适当加热后进行。Tempering: Although furnace tempering is preferred, tempering can be performed with a torch. The optimum tempering temperature for most alloy steels is

32、in the range of 400 to 450 F. There are two schools of thought with regard to tempering after flame hardening. One school professes that tempering is not necessary after flame hardening because the hardening effect is very shallow when compared to conventional furnace hardening. The other school pro

33、fesses that tempering after any kind of austenitizing and quenching operation is good practice and should be include as an integral part of every flame hardening operation. Proper tempering relieves quenching stresses and transforms unstable retained austenite to martensite upon cooling from the coo

34、ling temperature. If that is not done, the transformation of any unstable retained austenite to martensite may result in cracking of the part during service. It is strongly recommended that steels processed by flame hardening be tempered either with a torch pass or preferably in a furnace.回火：虽然首选火炉回

35、火，也可以使用焊枪。合金钢的最佳回火温度范围是400 to 450 F. 关于火焰硬化后的回火有2种理论。一种是硬化后无需回火，因为和传统的火炉淬火相比，这种硬化的效果欠佳。另一种说法是所有的奥氏体化和淬火操作后回火是好的，且应作为完整火焰淬火的一部分。适当回火可解除淬火应力将不稳定的残留的奥氏体通过冷却温度转化为马氏体。如果不这么做，奥氏体到马氏体的转换会导致鈑件开裂。强烈建议淬火后使用焊枪或熔炉回火。If a torch is used for tempering, the torch head should be designed correctly in termsof the num

36、ber and size of the orifices (flame ports) to produce the required work temperature and temperature uniformity in the flame-hardened zone at the flame- hardening speed. Flame heads used for tempering have less heat output than heads used for flame hardening for two reasons: (1) to avoid too rapidly

37、heating the hardened zone, which could result in cracking; (2) to ensure better control of the tempering operation so that hardness is not reduced to below the target hardness.如果使用焊枪回火，焊枪的管口的数量和大小的设计要正确，以达到火焰淬火部分要求的温度和温度的稳定性。用于回火的火焰头的热功率比用于火焰淬火的头小：（1）避免加热过快导致开裂；（2）更好的控制回火，所以硬度不会减少到目标硬度之下。DISTORTION

38、CAUSED BY FLAME HARDENING 火焰淬火导致的变形Flame hardening can be the cause of size change and distortion when the: 火焰淬火发生以下情况后会导致大小的变化和变形：1. Heating cycles are too long and nonuniform. 加热时间过长且不均匀。2. Quenching is nonuniform and quenching speeds are too fast.回火不稳定，过快。3. Shape of the work piece or configurati

39、on of the part to be hardened is not well adapted to flame hardening. 工件形状或需要硬化的鈑件和没有很好的适应火焰淬火。4. Metallurgy of the work piece has an unsuitable structure prior to flameHardening (material should be either in the properly annealed or properly heat- treated condition). 火焰淬火前，工件的冶金术结构不合理（材料要是合理的退火或热处理

40、状态。）5. Hardenability of the material is excessive, such as with air -hardening tool steels like S7, A2, and D2 that harden relatively deeply in still air.材料的淬硬性过高，比如使用蒸馏气体硬化相对深入的材料S7, A2, and D2的气体硬化的工具钢。It must also be kept in mind that size change and distortion that develop during flame hardening

41、 may be caused by a combination of residual stresses that developed during cold working (saw cutting, machining, etc.). In this case, a stress-relief cycle before flame hardening may work to minimize problems relating to size change and distortion during flame hardening. 必须注意的是火焰淬火中产生的大小变化和变形有可能是冷加工

42、过程中（锯切割，机加等）导致的残余应力造成的。这种情况下，淬火前的应力解除环节可以将火焰淬火过程中的大小变化和变形问题最小化。二、Flame Types for Flame Hardening火焰淬火的火焰类型Flame hardening experts favor a slightly carburizing flame in order to avoid the possibility of decarburizing the surface layer of the work piece. This can be accomplished by giving the outer fla

43、me tip a very slight feather. Note the flame sketches below. 火焰淬火专家优选轻微的碳化火避免表面脱碳。火焰外围为轻微羽状火焰。见下图。Four Basic Flame Types 4种基本类型The proportions of oxygen and the type of gas used will determine the characteristics of the resulting flames.氧气和气体的类型将决定生成火焰的特性。 Figuer 8-8 pure fuel gas flame 图8纯燃料气体火焰The

44、 pure gas type flame (Figure 8-8) is characterized by a heavilyfeathered tip that burns orange, yellow and blue as it goes back toward the torch tip. It is developed as the gas is ignited and the soot, smoke is adjusted out of the flame. 单一气体类型火焰（图8-8)的特点是有各种的羽毛状的橙色，黄色或蓝色火焰，当火焰返回至焊枪顶端。 再根据要求调整火焰 Fig

45、uer 8-9 C arburizing flame碳化火焰Carburizing flame (Figure 8-9) contains an excess amount of fuel. Thisflame is used during most flame hardening applications and will yield a work piece surface that is slightly carburized and higher in hardness. Compared to the neutral flame, the inner cone is larger a

46、nd tends to become feathered. 碳化火焰含有过量的燃油。大部分的火焰淬火都使用这种。能够使轻微碳化和硬度较高的工件表面获得屈服。和中性火焰相比，焰心较大且变为羽毛状。Figuer 8-10 Neutral flame 中性火Neutral flame (Figure 8-10) is developed by using equal amounts of oxygen and fuel mix. It is used for most flame hardening, cutting, and heating applications. This flame wil

47、l not carburize or decarburize the surface of the workpiece. No acetylene feather appears.中性火是由等量的氧气和燃料混合产生的。通常用于大部分的火焰淬火，切割，和加热等，这种火焰将不碳化或脱碳工件表面。没有乙炔羽毛状火焰出现。Figuer 8-11 -Oxidizing flame 氧化焰Oxidizing flame (Figure 8-11) contains an excess amount of oxygen. It isonly used on specific materials where

48、the development of decarburization will not be a problem. Compared to the neutral flame, the inner cone is smaller and slightly tighter.氧化焰含有过量的氧气，只用于脱碳不会有问题的特殊材质，和中性火焰 相比，馅心比较小且更紧凑三、Distortion and Size Change during Hardening淬火过程中的变形和尺寸变化Is Machining of Tools and Dies Too Close to Finished Dimensio

49、nsBefore Hardening a Gamble worth Taking? 是在淬火前将工具和模具加工接近精加工尺寸吗?There is an increasing trend to machine tools and dies closer and closer to finished dimensions before hardening. This is done in order to minimize the need for finish machining (grinding, EDM) of steels in the hardened condition, thus

50、lowering machining costs. Unfortunately, this is a dangerous practice because dimensional changes that occur during hardening frequently do not work out as planned. If sufficient stock is not left on a tool or die prior to heat treatment, the resultant combination of size change and/or distortion ma

51、y make it impossible to finish-machine the part to required dimensions. This section provides an overview of the sources of stresses that result in size change and distortion of tools and dies in heat treatment.淬火之前越来越倾向于先将模具等加工的和最终的尺寸越近越好。这么做目的是将硬化状态下精加工(研磨，电火花)的需要最小化，这样加工的费用就较低。但是这非常危险，因为淬火中发生的尺寸变

52、化不会像预计的灵验。如果热处理前，模具等上面的部件没有充分的库存，由于尺寸变化和变形导致的结果可能会使鈑件无法达到精加工的尺寸要求。这部分内容是导致热处理过程中尺寸变化和变形导致的压力源。First, it must be noted that nondeforming or distortion-free tool steels do not exist. All tool steels are subject to problems related to warpage (bending, bowing, twisting),in combination with growth or sh

53、rinkage when they are hardened. The degree of distortion depends on the amount of residual stresses that develop in the steel. Volume changes not only result in dimensional changes (growth or shrinkage) of the tool or die, but also increase the residual stress level. The following provides an explan

54、ation of the causes of size change and distortion:首先，必须指出不会变形的工具钢是不存在的。所有的工具钢都收硬化过程中的弯曲，扭曲有关。变形的程度取决于钢板上的残余应力大小,体积变化不仅仅会导致尺寸变化（变大，变小），也会增加残余应力。以下位大小变化和变形原因解释。1. Mechanically Induced Stresses:机械感应应力These stresses result from cold-working operations (machining, saw cutting, etc.). The magnitude of the

55、se stresses is in direct proportion to depth-of-cut, cutting speed, etc. If these stresses are not relieved before a tool or die is heat treated, they will be released during the heating for hardening and may result in distortion(Bending, bowing, and/or twisting).这些应力是由于冷加工导致的（机加，锯切等）导致的。应力大小和切割深度速度

56、等成正比。在热处理之前应力未解除，将在硬化加热过程中释放解除导致变形。（弯曲，顺弯或扭曲。）2. Thermal Stress Induced From Heating and Cooling: 加热和冷却导致的感应热应力Thermally induced stresses during heating and cooling also increase the residual stress level of a part.When steel is heated to the preheat and hardening temperature, it will expand. The ma

57、ss and design configuration of the tool or die being heat treated will determine how uniformly the part will expand during heating. Light cross sections expand more rapidly and will reach temperature before heavy sections. The surfaces of heavy cross sections will reach temperature before interior sections. The noted temperature differences