Duplex stainless steel wire material, steel wire, bolt, and method for production of the bolt

Abstract

Disclosed is an austenite-ferrite duplex steel wire material for a high-strength, high-corrosion-resistant bolt, which has excellent cold forgeability. The steel wire material comprises the following components (by mass): C: 0.005-0.05%, Si: 0.1-1.0%, Mn: 0.1-10.0%, Ni: 1.0-6.0%, Cr: 19.0-30.0%, Cu: 0.05-3.0% and N: 0.005-0.20%, with the remainder being Fe and substantially unavoidable impurities, wherein the total content of C and N is 0.20% or less, the M value represented by the formula (a) below is 60 or less, the F value represented by the formula (b) is 45 to 85, and the tensile strength is 550 to 750 N / mm2. M = 551-462(C+N)-9.2Si-8.1Mn-29(Ni+Cu)-13.7Cr-18.5Mo (a) F = 5.6Cr-7.1Ni+2.4Mo+15Si-3.1Mn-300C-134N-26.6 (b).

Description

technical field The present invention relates to a duplex stainless steel wire rod excellent in cold forgeability, and provides, for example, a high-strength bolt having corrosion resistance equivalent to that of SUS304 at low cost. The present invention relates to a soft duplex stainless steel wire material with magnetizability and excellent cold workability, and more specifically to screws, pins, metal meshes, steel wires, steel cables, springs, etc., which can be provided at low cost and have corrosion resistance equivalent to, for example, SUS304 and SUS316 Soft duplex stainless steel wire material with strong cold workability and excellent cold workability with magnetization imparted at the same time. This application claims priority based on Japanese Patent Application No. 2007-264992 filed in Japan on October 10, 2007, and Japanese Patent Application No. 2007-264993 filed in Japan on October 10, 2007, the contents of which are incorporated herein by reference. Backgr...

AI Technical Summary

Problems solved by technology

However, in the examples, the steel containing 0.08% or more of nitrogen to improve the strength is described in order to improve the deep drawability of the steel sheet by improving the ductility. Cold workability is difficult

As mentioned above, among the conventional stainless steels, there is no stainless steel that has the softness and high fracture shrinkage characteristics necessary for the cold workability of wire rods, and is inexpensive and exhibits high corrosion resistance and magnetization.

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