论文部分内容阅读
20世纪60年代开发和70～80年代处于逐步完善过程的真空渗碳技术,长期未得到广泛应用。主要问题是甲烷在低压下很难裂解,丙烷在真空中裂解后会形成大量炭黑。沉积在工件表面和炉壁上的炭黑一则阻碍工件的渗碳;二则污染炉膛和淬火油,三则油中淬火工件畸变严重,工件表面碳浓度高、脆性大。炭黑还会沉积在电阻发热体引出棒上,形成极间放电,导致石墨发热体损坏和降低热效率。直到90年代开发出利用乙烷、丙烷或丙烯的低压脉冲渗碳和低压渗碳—扩散过程优化方式以
The vacuum carburizing technology developed during the 1960s and gradually improved during the 1970s and 1980s has not been widely used for a long time. The main problem is that methane is hard to crack under low pressure and propane can form a large amount of carbon black after being cracked in a vacuum. One of the carbon black deposited on the surface of the workpiece and the furnace wall hinders the carburizing of the workpiece; the other two pollutes the hearth and the quenching oil; the three quenching parts in the oil have serious distortion; the carbon concentration on the surface of the workpiece is high and the brittleness is large. Carbon black will also be deposited in the resistance heating body lead rod, forming discharge between the electrodes, resulting in damage to the graphite heating element and reduce thermal efficiency. Until the 1990s, low-pressure pulsed carburization and low-pressure carburizing-diffusion processes using ethane, propane or propylene were developed to optimize