The casting process of silicon bronze: melting and pouring. Silicon bronze is smelted in an acid induction furnace. The charge should be preheated to 150~200℃ before being put into the furnace, and the electrolytic copper should be cleaned up, roasted at high temperature and thoroughly deoiled before use. The composition of Si is 3.1%, Mn is 1.2%, and the rest is Cu, plus Fe is 0.25% and Zn is 0.3%. Feeding order: first add 0.5% flux (boric acid + glass) of the charge amount, add crystalline silicon, manganese metal and electrolytic copper, increase the temperature to 1250℃, add iron and zinc, until the temperature rises to 1300℃, hold for 10 min, then sample and pour into the sand mold test block. If the test block is depressed in the middle after cooling, it means that the alloy is normal, slag scraping out of the oven and covered with perlite to prevent oxidation and inspiration.
The pouring temperature was 1090~1120 ℃. For large thin-walled parts, it is advisable to adopt top injection or side injection step gating system. When the pouring temperature exceeds 1150℃, hot cracking is easy to occur, while when the pouring temperature is below 1090℃, undercasting defects are easy to occur.
Compared with tin bronze (Sn 9%, Zn 4%, Cu), the solidification range of silicon bronze is 55℃, while that of tin bronze is 146℃, so its fluidity is higher than that of tin bronze. It can be seen that silicon bronze is much higher than tin bronze at the same pouring temperature.
The welding performance of silicon bronze, the welding performance of various copper alloys is divided into 4 grades according to their pros and cons, grade 1 is excellent, grade 2 is satisfactory, grade 3 is weldable by special process, grade 4 is unsatisfactory, Tin bronze is a grade 3, while silicon bronze is a grade 1.
Compared with other copper alloys, silicon bronze has lower thermal conductivity and does not need preheating before welding, but it has thermal brittleness in the range of 815~955℃. However, if the cast plate is of good quality, that is, the cast plate after adopting technical improvement measures, practice has proved that hot cracking will not occur in this temperature zone.
Silicon bronze can be gas welding, arc welding, manual TIG welding and MIG welding.
Post time: Aug-04-2022