Production method of low-hardness 20CrMnTi round steel

Abstract

The embodiment of the invention provides a production method of low-hardness 20CrMnTi round steel. The production method is characterized by comprising the following steps that a round steel blank isdesigned and controlled to comprise the components of 0.18 percent to 0.22 percent of carbon, 0.20 percent to 0.30 percent of silicon, 0.85 percent to 1.05 percent of manganese, 1.05 percent to 1.25 percent of chromium, 0.050 percent to 0.070 percent of titanium, 0.020 to 0.040 percent of aluminum and less than or equal to 0.0020 percent of oxygen; the round steel blank is smelted into molten steel through a steel furnace, and the molten steel is subjected to LF refining, RH vacuum treatment and continuous casting to form a continuous casting billet; the continuous casting billet is heated ina furnace in a three-stage manner, and after being heated, the continuous casting billet is rolled into rolled round steel through rough rolling, medium rolling and finish rolling mill units; the rolled round steel is subjected to controlled cooling through a water-passing cooler; and the rolled round steel enters a cooling bed for natural cooling after passing through water, wherein the temperature of the cooling bed when the round steel enters is controlled to be 930+ / -30 DEG C .

Description

technical field [0001] The invention belongs to the field of metallurgy, and in particular relates to a production method of low-hardness 20CrMnTi round steel. Background technique [0002] In recent years, my country's automobile, construction machinery and other industries have developed vigorously, and the domestic demand for 20CrMnTi series round steel is very strong. According to the statistics of China Association of Automobile Manufacturers and China Gear Professional Association, China's automobile production and sales will reach 28 million in 2019, and the consumption of automobile gear steel will be about 3.7 million tons. China's automobile production will grow at an average annual rate of about 10%. , analyzing the product composition of the automotive industry in recent years, it can be found that the fastest growing vehicles in the automotive industry are mainly heavy-duty trucks and cars. The most important consumer of gear steel. [0003] Gear steel has a w...

AI Technical Summary

Problems solved by technology

[0006] The use process of 20CrMnTi round steel at the user's place is generally: round steel → shearing or sawing blanking → heating → stamping → heat treatment, the first process in the user's use process is to cut according to the blanking size required by different workpieces Or sawing blanking, therefore, for the 20CrMnTi round steel with high hardness, defects such as chipping (or "lack of meat") will be caused during blanking, and such blanking parts cannot be subsequently stamped and formed, resulting in waste products. In addition, high-hardness round steel increases machine loss

[0009] In view of the high hardness of small-sized 20CrMnTi round steel, the production process has been optimized and improved, such as reducing the content of C, Mn, Cr and other elements within the standard range, and quickly sending it to the warehouse through the cooling bed for stack cooling and slow cooling after final rolling , but the improvement effect is not ideal