無(wú)縫異型鋼管為優(yōu)質(zhì)碳素結(jié)構(gòu)用鋼 ,硬度不高易切削加工,模具中常用來(lái)做模板,梢子,導(dǎo)柱等,但須熱處理 。 推薦熱處理溫度：正火850，淬火840，回火600。無(wú)縫異型鋼管淬火后沒(méi)有回火之前，硬度大于HRC55(最高可達(dá)HRC62)為合格。實(shí)際應(yīng)用的最高硬度為HRC55(高頻淬火HRC58)。 45號(hào)鋼不要采用滲碳淬火的熱處理工藝。 Cold-drawn seamless steel pipes are high quality carbon structural steels with low hardness and easy to cut. Dies are often used as templates, tips, guide pillars, etc., but heat treatment is required. Recommended heat treatment temperature: normalizing 850, quenching 840, tempering 600. The hardness of cold-drawn seamless steel tube is higher than HRC55 (up to HRC62) before quenching and tempering. The highest hardness in practical application is HRC55 (high frequency quenching HRC58). No. 45 steel should be treated by carburizing and quenching. 調(diào)質(zhì)處理后零件具有良好的綜合機(jī)械性能，廣泛應(yīng)用于各種重要的結(jié)構(gòu)零件，特別是那些在交變負(fù)荷下工作的連桿、螺栓、齒輪及軸類等。但表面硬度較低，不耐磨。可用調(diào)質(zhì)+表面淬火提高零件表面硬度。

After quenching and tempering, the parts have good comprehensive mechanical properties and are widely used in various important structural parts, especially those connecting rods, bolts, gears and shafts working under alternating loads. But the surface hardness is low and wear-resistant. Tempering and surface quenching can be used to improve the surface hardness of parts.

無(wú)縫異型鋼管滲碳處理一般用于表面耐磨、芯部耐沖擊的重載零件，其耐磨性比調(diào)質(zhì)+表面淬火高。其表面含碳量0.8--1.2%，芯部一般在0.1--0.25%(特殊情況下采用0.35%)。經(jīng)熱處理后，表面可以獲得很高的硬度(HRC58--62)，芯部硬度低，耐沖擊。

Carburizing treatment of cold-drawn seamless steel tubes is generally used for heavy-duty parts with wear-resistant surface and impact-resistant core, and its wear resistance is higher than that of quenching and tempering plus surface quenching. Its surface carbon content is 0.8-1.2%, and its core is generally 0.1-0.25% (in special cases, 0.35%). After heat treatment, the surface can obtain high hardness (HRC58-62), low core hardness and impact resistance.

如果用45號(hào)鋼滲碳，淬火后芯部會(huì)出現(xiàn)硬脆的馬氏體，失去滲碳處理的優(yōu)點(diǎn)。現(xiàn)在采用滲碳工藝的材料，含碳量都不高，到0.30%芯部強(qiáng)度已經(jīng)可以達(dá)到很高，應(yīng)用上不多見(jiàn)。0.35%從來(lái)沒(méi)見(jiàn)過(guò)實(shí)例，只在教科書里有介紹?？梢圆捎谜{(diào)質(zhì)+高頻表面淬火的工藝，耐磨性較滲碳略差。

If 45 steel is carburized, hard and brittle martensite will appear in the core after quenching, thus losing the advantage of carburizing treatment. At present, the material with carburizing process has not high carbon content, and the strength of 0.30% core has reached a high level, which is rarely used. 0.35% had never seen an example, only introduced in textbooks. The process of quenching and tempering plus high frequency surface quenching can be adopted, and the wear resistance is slightly worse than that of carburizing.

GB/T8162-2008標(biāo)準(zhǔn)規(guī)定的45號(hào)鋼無(wú)縫異型鋼管推薦熱處理制度為850℃正火、840℃淬火、600℃回火，達(dá)到的性能為屈服強(qiáng)度≥355MPa。GB/T699-1999標(biāo)準(zhǔn)規(guī)定45鋼抗拉強(qiáng)度為600MPa，屈服強(qiáng)度為355MPa，伸長(zhǎng)率為16%，斷面收縮率為40%，沖擊功為39J。

According to GB/T8162-2008 standard, the recommended heat treatment system for cold-drawn seamless steel pipe 45 is normalizing at 850 (?), quenching at 840 (?) and tempering at 600 (?) C. The yield strength of the steel 45 is more than 355 MPa. GB/T699-1999 standard stipulates that the tensile strength of 45 steel is 600 MPa, the yield strength is 355 MPa, the elongation is 16%, the section shrinkage is 40%, and the impact energy is 39 J.