High-strength invar alloy and its alloy wire rod production method

Abstract

A high intensity invariable steel and a production method for it's wire rod characterizes in taking Fe-36Ni alloy as the base added with W, V and C in the following weight percentage: C 0.15 to 0.40, Si is not greater than 0.60, Mn is not greater than 0.8, p is not greater than 0.025, S is not greater than 0.02, Ni: 34.0 to 42.0, co is not greater than 3.5, Cr is not greater than 0.5, Cu is not greater than 0.2, W: 1.5 to 5.0, v 0.3 to 1.2, Mo is not greater than 0.5, the rest is Fe and unavoidable impurities, W.V is greater than 1.5, c=0.9-1.3(0.033w+0.2V). The production method includes: 1, processing the steel ingot into rods then to wire rods (phi=10 to 15mm) 2, applying special twice cold processing deformation and hot process, the twice cold-draw deformations are 20-70%, 55 to 95% then they are hot processed under 450-750 DEG C.

Description

technical field [0001] The invention relates to the composition design of low-expansion Invar alloy and its manufacturing method, in particular to the manufacturing method of high-strength Invar alloy wire. Background technique [0002] Invar alloy is a special alloy, Fe-36Ni Invar alloy (4J36 alloy) is a common Invar alloy, since its invention in 1893, because of its very low expansion coefficient (expansion coefficient is closely related to alloy material and service temperature: Different materials have different expansion coefficients; the same alloy material has a high service temperature and a high average expansion coefficient α. The expansion coefficient of Fe-36Ni Invar alloy is very low, only 1 / 5 to 1 / 10 of that of ordinary materials. For 4J36 For alloys, the GBn 110-87 standard stipulates that at 20-100 °C, α≤1.5×10 -6 / °C; Generally speaking, the recommended value of α in kind is: 20~100°C, α=0.8×10-6 / °C, 20~200°C, α=2.0×10 -6 / °C, at 20~300°C, α=5.1×10 -6 / °C...

AI Technical Summary

Problems solved by technology

[0005] At present, there are three main ways to manufacture high-strength Invar alloys: (1) The first one is based on Fe-36Ni alloy, by adding Be, using the Ni3Be intermetallic compound strengthening mechanism to achieve alloy strengthening. The advantages of this method are The strengthening effect is good (tensile strength ≥ 1500MPa), and the disadvantage is that the expansion coefficient of the alloy is high (20-100°C, α=3.5-4×10 -6 / °C), and the alloy has a high martensitic transformation point, which is not suitable for use at low temperatures. What is more serious is that the added Be element is highly toxic, which is not conducive to environmental protection

(2) The second method is based on Fe-36Ni alloy, by adding carbon and carbide forming elements to achieve the purpose of improving the strength of the alloy, usually by adding C and V to precipitate vanadium carbide in the alloy, relying on this precipitation strengthening Improve the strength of the alloy, but in the case of only adding V, the VC precipitates tend to become coarse particles, which cannot achieve sufficient high strength, and the general strength is less than 1100Mpa; (3) The third method (Japan Daido Special Steel Co., Ltd. PCT patent application, international publication number: WO 03 / 025239A1) is basically similar to the second method, based on Fe-36Ni alloy, the purpose of improving the strength of the alloy is realized by adding carbon and carbide forming elements, and simultaneously adding C and Mo, The method of V suppresses the coarsening of carbides and effectively improves the strength and torsional properties of alloys (tensile strength ≥ 1300MPa, torsional value ≥ 20). The disadvantage is that the expansion coefficient of alloys with Mo and V added at the same time is high, 20-230 ℃ and 230~290℃ temperature range, the average linear expansion coefficients are ≤3.7×10 -6 / °C and ≤10.8×10 -6 / °C