Process steps

Up-induction continuous casting: high purity cathode copper, Copper-Silicon master alloy, copper-manganese master alloy, copper-magnesium master alloy, copper-phosphorus master alloy, copper-tin master alloy, pure zinc, copper-indium master alloy are used as raw materials to melt and up-induction continuous casting in a smelting device. The smelting device includes a melting furnace and a holding furnace, in which the melting furnace temperature is 1150 (+5) and the holding furnace temperature is 1130 (+5). The charcoal covered in the melting furnace has a particle size of 60 mm-80 mm, a covering thickness of 150 MM-200 mm, and graphite flakes covered in the holding furnace with a covering thickness of 50 mm-100 mm. The diameter of the upper lead-in copper rod is 20 mm, the diameter tolerance of the upper lead-in copper rod is less than (+0.1 mm), and the drawing speed of the upper lead-in copper rod is 550-600 mm/min.

Continuous extrusion: using the above lead-in copper rod as raw material, the silicon bronze rod with a diameter of 20 mm is prepared by continuous extrusion machine; the rotating speed of the continuous extrusion machine is 7-8 r/min, the temperature of continuous extrusion is more than 700 C, the extrusion pressure is more than 1100 MPa, the gap between shoe seat and extrusion wheel in the continuous extrusion machine is 0.10-0.12 mm, and the compression pressure of shoe seat is 20-30 MPa. The diameter of the wheel is 630 mm and the width of the extrusion wheel is 150 mm. The silicon bronze rod is cooled by the continuous extrusion unit with 30% alcohol aqueous solution. After cooling, the temperature of the silicon bronze rod is less than 50 C, and the grain size of the prepared silicon bronze rod is 0.007-0.015 mm.

Skin scraping: The silicon bronze rod was skinned, and the diameter of the silicon bronze rod was 18 mm after skinning.

Rolling: the silicon bronze bronze wire with diameter of 3mm was obtained by rolling and rolling the silicon bronze rod, and the emulsion was lubricated and cooled during rolling. The emulsion concentration was 12% ~ 15% and the temperature was less than 40 C.

Heat treatment: temperature 600 C, time 3 hours;

Wire drawing: continuous drawing of wire drawing machine to a diameter of 1.2mm, the emulsion's concentration is 10% to 12%, and the temperature is less than 35 C.

Stress relief annealing: temperature 250 C, time 1 hour, using gas protection measures to prevent oxidation;

The tensile strength and elongation of the silicon bronze wire prepared by the above steps are greater than 400 MPa and 50%.

Product introduction

Silicon bronze welding wire is widely used in automobile body surface welding because of its low melting point, good welding process performance and beautiful welding seam. China patent CN201210456208 and China patent CN201710128381 disclosed the related technology of silicon bronze wire for automobile welding. However, the silicon content in the two patented silicon bronze alloys is higher, and brittle phase Mn2Si is easy to form when the silicon content is higher, which makes the alloy prone to self-cracking. At the same time, the technology disclosed in the patent is smelting, continuous casting (up-drawing continuous casting), cold rolling (rolling) and other processes for processing. Because the as-cast structure has not been hot-processed, the material performance has not reached the optimum.