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低Al—Cr氮化钢(C0.14%,Cr0.95%,Al0.27%),在仅用N_2+H_2混合气离子氮化时,化合物层形成针状γ′,脆性大。为防止形成针状γ′,向N_2+H_2混合气中添加3%的CH_4,针状γ′消失,成为ε,得到致密的化合物层。其渗层硬度梯度和不加CH_4时一样。使用N_2:H_2=70:30,570℃处理,处理1～10小时,表面硬度为Hv860～890(距表面0.025mm处);处理7～10小时,氮化层深度(Hv513以上)达0.3mm以上;而添加3%CH_4,则表面硬度达Hv970,氮化层深度有些减少。但此结果和SACM1钢相比,虽表面硬度有些低,而氮化深度却显著增大。
Low Al-Cr nitrided steel (C0.14%, Cr0.95%, Al0.27%), the compound layer formed acicular γ ’with large brittleness when it was nitrided by N 2 + H 2 mixed gas. In order to prevent the formation of acicular γ ’, 3% CH 4 was added to the N 2 + H 2 mixture, and acicular γ’ disappeared and became ε, resulting in a dense compound layer. The infiltration hardness gradient and the same as without CH_4. The surface hardness is Hv860 ~ 890 (0.025mm from the surface) when treated with N_2: H_2 = 70: 30,570 ℃ for 1 to 10 hours; the depth of nitrided layer (Hv513 and above) reaches 0.3mm or more when treated for 7 to 10 hours; The addition of 3% CH_4, the surface hardness of Hv970, nitrided layer depth somewhat reduced. However, compared with SACM1, the results show that although the surface hardness is somewhat lower, the nitriding depth is significantly increased.