HRB 400 steel bar production method

The invention relates to a production method of an HRB400 steel bar, and the material of steel bloom is 20MnSi by component optimization. The technical process comprises bessemerizing, argon-blowing refinement, continuous casting, lower-temperature rolling, rolling control among machines and stepping cooling control after rolling; and recovering sections are arranged among cooling sections. The adoption of the technology for producing the HRB400 steel bar, not only can greatly reduce cost, but also can degrade the requirements on the capacity of rolling mills and cooling control equipment among the machines so as to improve the applicability thereof. The product specifications range phi 10-phi40mm, the produced HRB400 steel bar has stable structure property and good welding and anti-quake properties.