高压泥浆阀阀板及阀杆的气体渗氮

Gas Nitriding for Plate and Stem of High Pressure Mud Valve

高压泥浆阀板和阀杆材料分别为35CrMo钢和1Cr13不锈钢,在200℃左右的腐蚀性介质中服役,均要求进行渗氮处理,以提高其耐磨性和耐蚀性。经过多次试验,最终确定采用氮碳共渗,工艺参数为:对于阀板,温度530～540℃,保温时间约10 h,保温期前7 h氨分解率30%～40%,乙醇约1 ml/min,后3～4 h氨分解率60%～80%,乙醇约1.5 ml/min;对于阀杆,温度为500～520℃,其余参数同阀板。

Plate and stem of high pressure mud valve made of 35CrMo steel and 1Crl3 stainless steel respectively are exposed to corrosive medium at about 200 ℃in service, and hence are be nitrided to improve on the wear and corrosion resistances. After being repeatedly experimented, finally determined nitrocarburizing process is as follows： 530 to 540℃ for about l0 h; ammonia dissociation rate of 30% to 40% plus alcohol of about 1 ml per rain in the first 7 h of the holding period; ammonia dissociation rate of 60% to 80% plus alcohol of about 1.5 ml per min in the later 3 to 4 h of the holding period for the valve plate. For the valve stem, the nitrocarburizing temperatures vary from 500 to 520 %, and the rest is the same as those for the valve plate.