熱處理工藝對12Cr1MoVG厚壁無縫鋼管表面硬度的影響
Effect by Heat Treatment on Surface Hardness of 12Cr1MoVG Heavy-wall Seam less Steel Tube
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摘要: 分析了12Cr1MoVG厚壁無縫鋼管組織分布狀態(tài)與硬度的關(guān)系；通過測定其CCT曲線，確定出Φ219mm×45 mm規(guī)格12Cr1MoVG厚壁無縫鋼管的最佳熱處理工藝：淬火970℃×60 min、水淬20 s，回火750℃×150min。生產(chǎn)結(jié)果表明：通過控制淬火時間，可減少鐵素體的析出量，避免馬氏體組織的大量析出，從而實現(xiàn)產(chǎn)品硬度的控制；新熱處理工藝實現(xiàn)了12Cr1MoVG厚壁無縫鋼管硬度在161～182 HB內(nèi)的穩(wěn)定控制，表面硬度合格率達100%，且其各項機械性能指標(biāo)均滿足標(biāo)準(zhǔn)要求。Abstract: Investigated in the article is the relationship between the micro-structural distribution status of the 12Cr1MoVG heavy-wall seam less steel tube and its surface hardness.Based on the measured CCT curve of it，the optimum heat treatment process for the Φ 219mm×45mm 12Cr1MoVG heavy-wall tube is determined，involving such critical parameters as furnace quenching：temperature 970 ℃，time 60minutes；water quenching：time 20 s；tempering：temperature 750℃，time 150minutes.The actual operation result of the said heat treatment process demonstrates that with proper control of the quenching time，the ferrite segregation amount can be reduced，so as to prevent remarkable segregation of the martensitic structure，and thus get satisfactory control of the product hardness.The newly-set heat treatment process ensures that the hardness range of the 12Cr1MoVG heavy-wall tube is consistently kept as 161～182 HB，and the surface hardness qualification rate thereof is up to 100%，while all the other mechanical property data are in compliance with relevant requirements under the applicable product standard.
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