周修文论文中英文翻译.docx

Carburizing and prevent the common defects(a) carbon concentration is too high Same reason and harm: if carburizing sharply when heated, the temperature is too high or solid carburizing with new when carburizing agent, or with a strong push permeability agent too much can cause carburizing high concentration of the phenomenon. With high carbon concentration, the surface appears bulky carbon block or reticular carbide. Because of this hard brittle organization produce, make carburized layers toughness fell sharply. And hardened high carbon martensite formation, was easy to appear in the grinding grinding crack. 2. Prevent method (1) cant sharp heating, need to use the proper heating temperature, dont make the steel grain growth as well. If carburizing when coarse grains, should be in carburizing is fire or two after quenching process to fine grains. (2) the strict control furnace temperature uniformity, not too much volatility in FanSheLu solid carburizing should pay special attention. (3) solid carburizing, carburizing agents to use new and old ratio. Push permeability agent had better use 4-7% of BaCO3, do not use Na2CO3 be push permeability agent. (2) low carbon concentration But a cause and harm: temperature fluctuations very large or push permeability agent can cause less surface of carbon insufficient density. The most ideal carbon concentration of 0.9-1.0% between, less than 0.8% C, parts easy to wear. 2. Way to prevent: (1) the average temperature carburizing with 920-940 , low temperature of carburizing would cause the carbon concentration is too low, and extend the carburizing time; Carburizing higher temperature can cause coarse grains. (2) urged the permeability agent (BaCO3) should be no less than the amount of 4%. (3) carburizing partial surface after poor carbon: But a cause and harm: solid carburizing, charcoal particles too big or mixed stone etc impurities, or push permeability agent and charcoal mix the map, or workpiece contact with will cause local carbon or poor carbon. The dirt from the surface of workpiece can also cause poor carbon. 2. Prevent method (1) solid carburizing agent must be made in proportion, stir well. (2) the workpiece with furnace attention do not have contact. Solid carburizing keep Carburizing agent dao in reality, and dont make carburizing collapse and have the contact. (3) in the dirt from the surface but. (4) carburizing increased concentration of transition But a cause and harm: carburizing concentration is suddenly transition centre and the surface of the carbon concentration change intensifies, not from high to low even transition, but suddenly transition. The reason causing the defects is carburizing agent role very strong (such as new configuration of charcoal, old carburizing agent with very little), and steel in Cr, Mn, Mo alloy elements such as to form carbide is strong, and cause surface high concentration, the center low concentration, and no transition layer. Produce the defect caused considerable list after stress, the hardening process or the grinding process crack or spalling phenomena. 2. Way to prevent: carburizing agent according to regulations of the old and new ratio, carburizing moderate. As with BaCO3 urged the permeability agent is good, because Na2CO3 more sharply. (5) grinding generated when the tempering and crack The reasons of the same: carburizing layer caused by grinding surface after the softening of phenomenon, called grinding produce temper. This is because when grinding machining feeding too fast, grinding wheel hardness and particle size or improper selection speed, or the grinding process cooling is not full, are easy to produce such defects. This is because the surface grinding heat softenings sake. Grinding generated when the tempering defects is parts wear resistance decreased. Surface produces hexagonal crack. This is because the surface with hard grinding wheel by excessive grinding, and fever be caused by. Also and heat treatment tempering shortage, residual stress on too. After the use of acid erosion, always have defective parts been black, but with no defect place from the rest. This is when grinding generates heat temper. Make the horse make body change for the sake of difference of body tissue. In fact, crack in the naked eye can see after grinding. 2. Way to prevent: (1) must be hardened after full tempering or more tempering, eliminate stress. (2) an from 40 to 60 particle size of soft or middle alumina grinding wheel, grinding feeding but big. (3) when a cooling fluid grinding first, and pay attention to in the process of grinding sufficient cooling 渗碳的常见缺陷及其防止(一)碳浓度过高 产生原因及危害：如果渗碳时急剧加热，温度又过高或固体渗碳时用全新渗碳剂，或用强烈的催渗剂过多都会引起渗碳浓度过高的现象。随着碳浓度过高，工件表面出现块状粗大的碳化物或网状碳化物。由于这种硬脆组织产生，使渗碳层的韧性急剧下降。并且淬火时形成高碳马氏体，在磨削时容易出现磨削裂纹。 防止的方法 不能急剧加热，需采用适当的加热温度，不使钢的晶粒长大为好。如果渗碳时晶粒粗大，则应在渗碳后正火或两次淬火处理来细化晶粒。 严格控制炉温均匀性，不能波动过大，在反射炉中固体渗碳时需特别注意。 固体渗碳时，渗碳剂要新、旧配比使用。催渗剂最好采用47%的BaCO3，不使用Na2CO3作催渗剂。 (二)碳浓度过低 产生的原因及危害：温度波动很大或催渗剂过少都会引起表面的碳浓度不足。最理想的碳浓度为0.91.0%之间，低于0.8%C，零件容易磨损。 防止的方法： 渗碳温度一般采用920940，渗碳温度过低就会引起碳浓度过低，且延长渗碳时间；渗碳温度过高会引起晶粒粗大。 催渗剂(BaCO3)的用量不应低于4%。 (三)渗碳后表面局部贫碳： 产生的原因及危害：固体渗碳时，木炭颗粒过大或夹杂有石块等杂质，或催渗剂与木炭拌得不均匀，或工件所接触都会引起局部无碳或贫碳。工件表面的污物也可以引起贫碳。 防止的方法 固体渗碳剂一定要按比例配制，搅拌均匀。 装炉的工件注意不要有接触。固体渗碳时要将 渗碳剂捣实，勿使渗碳过塌而使工件接触。 却除表面的污物。 (四)渗碳浓度加剧过渡 产生的原因及危害：渗碳浓度突然过渡就是表面与中心的碳浓度变化加剧，不是由高到低的均匀过渡，而是突然过渡。产生此缺陷的原因是渗碳剂作用很强烈(如新配制的木炭，旧渗碳剂加得很少)，同时钢中有Cr、Mn、Mo等合金元素是促使碳化物形成强烈，而造成表面高浓度，中心低浓度，并无过渡层。产生此缺陷后造成表里相当大的内应力，在淬火过程中或磨削过程中产生裂纹或剥落现象。 防止的方法：渗碳剂新旧按规定配比制，使渗碳缓和。用BaCO3作催渗剂较好，因为Na2CO3比较急剧。 (五)磨加工时产生回火及裂纹 产生的原因：渗碳层经磨削加工后表面引起软化的现象，称之为磨加工产生的回火。这是由于磨削时