執(zhí)行歐洲標(biāo)準(zhǔn)S460NL高韌性結(jié)構(gòu)管的開發(fā)
Development of EN S460NL High-toughness Structure-purpose Pipe
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摘要: 在20Mn鋼的基礎(chǔ)上，通過添加Cr、Mo、Cu、Ni、V等合金元素，采用正火處理工藝生產(chǎn)了S460NL鋼管材料；分析了S460NL鋼管的顯微組織和力學(xué)性能。結(jié)果表明：該產(chǎn)品的金相組織為珠光體+彌散分布著細(xì)小碳化物的鐵素體基體，在拉伸過程中產(chǎn)生位錯塞積，從而使得鐵素體基體內(nèi)產(chǎn)生位錯纏結(jié)與網(wǎng)格結(jié)構(gòu)；沖擊斷口呈現(xiàn)出典型的韌窩特征。這些微觀特征決定了S460NL鋼管在獲得高強(qiáng)度的同時(shí)還具有優(yōu)良的耐低溫沖擊韌性：屈服強(qiáng)度>500 MPa，抗拉強(qiáng)度640～680 MPa，伸長率≥22%，-50℃沖擊功>100 J，滿足客戶要求。Abstract: The EN S460NL steel pipe is development by means of adding chemical elements like Cr，Mo，Cu，Ni and V，etc.into the 20Mn steel，and the pipe normalization heat treatment process.Microstructure and mechanical properties of the said pipe are tested.The test results reveal the facts as below.The metallographic structure of the pipes is of pearlite+ferrite matrix with dispersion-distributed fine carbides.And during the tensile testing process，the said fine carbides are dislocated and piled up，which leads to the development of dislocation tangling and network structure inside the ferrite matrix.The impact fracture has the typical tough dimple characteristics.All these microstructure characteristics enable the S460NL steel pipe to possess not only high strength，but also excellent low-temperature impact toughness，i.e.，yield strength>500 MPa，tensile strength：640-680 MPa，elongation rate≥22%，and impact energy at-50℃>100 J，and thus to have met the customer-specified requirements.
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