In 1961, the Beijing second machinetoolplant began using gas nitriding quenching.
1961年，北京第二机床厂开始采用气体氮化淬火。
2
Companies are Jinan first machinetool works, Sichuan Changzheng machinetoolPlant of the network company.
公司是济南第一机床厂、四川长征机床厂的网点公司。
3
Hebei Dongfeng Forming Machinery co., Ltd., the predecessor of Hebei is forging machinetoolplant, built in 1956, 1998 conversion to joint-stock enterprises.