ML20MnTiB 高强度冷镦钢线材的研制与开发

紧固件制造要求ML20MnTiB冷镦钢线材提高冷加工性能、淬透性和综合力学性能。安钢采用100 t转炉—LF精炼—150 mm×150 mm连铸小方坯—高速线材生产线,研制开发出ML20MnTiB高强度冷镦钢线材,主要化学成分如下:w(C)为0.19%~0.22%,w(Si)为0.08%~0.20%,w(Mn)为1.40%~1.55%,w(Ti)为0.04%~0.06%,w(B)为0.000 5%~0.002 5%。冶炼过程中控制硼不被氧化和氮化,轧制过程中开轧温度为(950±30)℃;精轧温度为(870±20)℃;减定径温度为(830±20)℃,吐丝温度为(800±20)℃,入口辊道速度为12~18m/min。生产实践表明:产品综合性能稳定,各项技术指标达到用户制作10.9级高强度螺栓的要求。

Research and development of ML20MnTiB high strength cold heading wire rod

Fastener production requires ML2OMnTiB cold heading wire rod to improve cold producing property, hardenability and comprehensive mechanical property. The 100 t BOF-LF refining process-150 mm× 150 mm continuous casting-high billet speed wire production line were adopted by Angang. The chemical compositions of ML20MnTiB high strength cold heading steel wire rod researched and developed are as follows ： w （C） is 0.19% - 0.22% , w （ Si ） is 0.08% - 0.20% , w（Mn） is 1.40% - 1.55% ,w（Ti） is 0.04% - 0.06% ,w（B） is 0. 000 5% - 0. 002 5%. To control B cant be oxidized and nitrided in the smelting process. In the rolling process, initial rolling is at （950 ± 30） ℃, finish rolling is at （870 ± 20） ℃ ,size reducing is at（830 ±20） ℃ , wire laying is at（800 ±20） ℃, entrance roller speed is 12 - 18 m/min. Production practice shows that integrated cold heading property keeps stable and each technical index has reached the requirements of 10.9 grade high strength bolt.