4results about How to "Improved cold working properties" patented technology

The application belongs to the technical field of stainless steel preparation, and discloses a cold-deformable and heat-treatable hardening Ni-free high-strength stainless steel and a preparation method thereof. The stainless steel comprises the following components in percentage by mass: Cr: 13-15%, C: 0.25-0.4%, Mn: 0.5-2%, Cu: 0.1-3%, Mo: 2-3%, Si: 0-0.5%, and the balance of Fe and inevitable impurities. The stainless steel does not contain Ni element, has a low work hardening rate (strain hardening index n≤0.185) and a fracture elongation rate of more than 20% in a soft state (annealed state), is cold-deformable, and has low raw material and processing costs; after quenching and aging heat treatment, the stainless steel not only has an optimal combination of strength and toughness (yield strength and tensile strength are more than 1300 MPa and 1600 MPa respectively, and elongation is greater than 10%), but also has a high yield strength ratio.

The present application relates to a kind of high-precision cold-rolled screw with medium carbon steel hot rolled wire rod in metallurgical technology field, preparation method and application.The present application is aimed at solving the technical problems of low first processing qualified rate of cold-rolled screw caused by poor material organization uniformity and low purity.The chemical composition of the wire rod according to the present application is as follows: C 0.52-0.58%, Si 0.15-0.35%, Mn 0.70-0.90%, Cr 0.10-0.35%, Al 0.015-0.045%, Ti≤0.0025%, [O]≤0.0015%, [N]≤0.0060% and the like, with the balance being Fe.The preparation method of the present application obtains uniform organization with cross-section hardness range ≤20HV through the combined action of narrow component design, continuous casting end electromagnetic stirring, high temperature diffusion annealing and "fast first and slow later" controlled cooling process.The present application is mainly used for manufacturing high-precision ball screw, and the finished product precision reaches more than 5 levels, with first cold-rolled forming qualified rate ≥85%.

This disclosure provides a steel sheet with excellent hardenability and excellent cold workability. The steel sheet disclosed herein has the following composition by mass %: C: 0.15~0.50%, Si: 0.01~0.50%, Mn: 0.20~1.30%, P: less than 0.100%, S: less than 0.100%, Al: less than 0.100%, Cr: 0.01~1.20%, N: less than 0.0150%, and the balance being Fe and impurities. The total surface area of ​​ferrite and cementite particles is 95% or more, the average grain size of ferrite is 5.0~20.0 μm, and the Cr concentration in the cementite particles is [Cr]. θ and Mo concentration [Mo] θ To satisfy equation (1), the average particle size of the cementite particles is less than 1.50 μm, the spheroidization rate of the cementite particles is greater than 70% and less than 85%, and the dispersion DI of the number of cementite particles in a small square partition with a side length of 10 μm, as defined by equation (2), is less than 45%. 2[Cr] θ +3[Mo] θ ≤3 / √C (1) DI=σ θ / N θ ×100 (2)

This disclosure provides a steel sheet with excellent hardenability and excellent cold workability. The steel sheet disclosed herein has the following composition by mass %: C: 0.15~0.50%, Si: 0.01~0.50%, Mn: 0.20~1.30%, P: less than 0.100%, S: less than 0.100%, Al: less than 0.100%, Cr: 0.01~1.20%, N: less than 0.0150%, and the balance being Fe and impurities. The total surface area of ​​ferrite and cementite particles is 95% or more, the average grain size of ferrite is 5.0~20.0 μm, and the Cr concentration in the cementite particles is [Cr]. θ and Mo concentration [Mo] θ To satisfy equation (1), the average particle size of the cementite particles is less than 1.50 μm, the sphericity of the cementite particles is greater than 85%, and the dispersion DI of the number of cementite particles in a small square partition with a side length of 10 μm, as defined by equation (2), is less than 45%. 2[Cr] θ +3[Mo] θ ≤3 / √C (1) DI=σ θ / N θ ×100 (2)