Solid stabilizer, steel material for solid stabilizer and method for producing solid stabilizer

Abstract

A steel material for a solid stabilizer which has high bendability, high hardenability, and high quenching crack resistance, a solid stabilizer having high strength, and a manufacturing method of the solid stabilizer. The steel material for the solid stabilizer contains, in mass %, 0.24 to 0.40% of C, 0.15 to 0.40% of Si, 0.50 to 1.20% of Mn, 0.03% or less of P, 0.30% or less of Cr, 0.01 to 0.03% of Ti, and 0.0010 to 0.0030% of B. The steel material for the solid stabilizer satisfies a condition of formula (1) below. Hardness in a radial center portion of the steel material for the solid stabilizer after tempering is 400 HV or more, and a martensite ratio in the radial center portion after the tempering is 80% or more. 1.24<(2C+0.1Si+0.4Mn+0.4Cr)×{1+(1.5B−300B2)×240}<1.7   (1) It is an object to provide a steel material for a solid stabilizer which has high bendability, high hardenability, and high quenching crack resistance, a solid stabilizer having high strength, and a manufacturing method of the solid stabilizer. The steel material for the solid stabilizer contains, in mass %, 0.24 to 0.40% of C, 0.15 to 0.40% of Si, 0.50 to 1.20% of Mn, 0.03% or less of P, 0.30% or less of Cr, 0.01 to 0.03% of Ti, and 0.0010 to 0.0030% of B. The steel material for the solid stabilizer satisfies a condition of formula (1) below. Hardness in a radial center portion of the steel material for the solid stabilizer after tempering is 400 HV or more, and a martensite ratio in the radial center portion after the tempering is 80% or more. 1.24<(2C+0.1Si+0.4Mn+0.4Cr)×{1+(1.5B−300B2)×240}<1.7   (1)

Description

technical field [0001] The invention relates to a solid stabilizer bar, a steel material for the solid stabilizer bar and a manufacturing method of the solid stabilizer bar. The solid stabilizer bar is used to ensure the stability of the vehicle when the vehicle is running. Background technique [0002] The stabilizer bar is connected to the suspension located on both sides in the vehicle width direction. The lateral roll of the vehicle is controlled by the stabilizer bar while the vehicle is in motion. There are solid stabilizer bars made of solid steel and hollow stabilizer bars made of hollow steel. In recent years, in order to reduce the weight of vehicles, people have increasingly used hollow stabilizer bars. For example, Patent Document 1 discloses a welded steel pipe for manufacturing a hollow stabilizer, and Patent Document 2 discloses a method for manufacturing a hollow stabilizer. [0003] Patent Document 1: Japanese Invention Patent Laid-Open No. 2004-11009 ...

AI Technical Summary

Problems solved by technology

However, in order to increase the strength, increasing the content of C, etc., which is effective for increasing the strength, will reduce the above-mentioned bending workability and quenching crack resistance. Therefore, when manufacturing a solid stabilizer bar with excellent strength compared with a hollow stabilizer bar Sometimes there is a problem that even if the technology used for the hollow stabilizer bar is applied to the solid stabilizer bar without modification, it is difficult to obtain the desired characteristics

[0011] As explained above, even if the steel for the hollow stabilizer bar is applied to the steel for the solid stabilizer bar without modification, the properties required for both are completely different, so the bending processability, quenching performance, and quenching crack resistance cannot be satisfied. , strength and other characteristics of all requirements

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