Method for producing tin phosphorus bronze band by direct cold cogging

Abstract

The invention discloses a method for producing a tin phosphorus bronze band by direct cold cogging, comprising: charge mixture, materials are melted and then transferred into a heat preserving furnace with the copper liquid temperature being 1140-1200 DEG C; horizontal casting is carried out, and roll blank having the thickness of 14.0-16.5mm, the width of 210-430mm and the length of 45-68mm can be obtained by the technique of pulling, stopping and reversely pushing; face-milling is carried out on the roll blank, and every side is milled by 0.5-0.8mm; then, direct cold cogging rolling is carried out for a first time, and a coiled stock having the thickness of 5.6-9.2mm can be obtained by rolling; intermediate annealing is carried out on the coiled stock in a bell jar furnace for a first time, the annealing temperature is 520-640 DEG C, and the heat preservation lasts for 4.5-6h; after that, the steps of crude rolling thinning, secondary intermediate annealing, surface cleaning passivation, cold fine rolling, low temperature heat treatment of finished product, surface cleaning passivation and stretch bending leveling are sequentially carried out, so that the tin phosphorus bronze band can be prepared. The method omits the operation of band blank homogenizing annealing, so as to obviously reduce the production cost as well as the consumption of manpower, liquid ammonia, liquid nitrogen, etc.

Description

technical field [0001] The invention relates to a method for manufacturing a tin-phosphorus bronze strip used in the electronics, electrical and mechanical industries, in particular to a method for directly cold blanking the tin-phosphorus bronze strip. Background technique [0002] Tin phosphor bronze containing more than 4% tin is usually not hot-rolled because of its narrow thermoplastic temperature range and severe hot-rolling cracking. Mainly due to the characteristics of the chemical composition of tin phosphor bronze, the cast tin phosphor bronze strip blank has serious reverse segregation phenomenon and casting internal stress. The reverse segregation leads to uneven chemical composition and plasticity decline of the strip, and casting stress leads to obvious plasticity decline and deformation. Resistance has also increased. However, the traditional methods both at home and abroad use strip uniform annealing to eliminate segregation, improve strip plasticity, and re...

AI Technical Summary

Problems solved by technology

However, the strip homogenization annealing in the above-mentioned production process is a rather time-consuming and power-consuming process, which is usually carried out in a bell furnace. The strip homogenization annealing temperature is 670-710°C, generally 16-20 hours. Each ton of tin bronze belt consumes about 100 degrees of electricity, 1.5 liters of liquid nitrogen, and 1.2 kg of liquid ammonia, which greatly increases production costs and relatively poor economic benefits.

[0003] With the existing industrial technology, no matter how high the homogenizing annealing temperature and how long the holding time is used, there is no obvious improvement effect on the regional segregation. The homogenizing annealing of the billet can only eliminate the intragranular segregation and eliminate the casting internal stress.

The intragranular segregation can be completely eliminated by several times of intermediate annealing, but because the plasticity of the general casting strip is too low, the edges are broken after rolling, and there are many broken strips, which reduces the yield. If the processing rate of cold billet rolling is too small, If the thickness after rolling is too large, it will inevitably increase the number of intermediate annealing in the future, and the economic benefit is not very obvious