Vacuum brazing technology of oil-water compound cooler

Vacuum brazing technology of oil-water compound cooler belongs to vacuum brazing technology.
The process parameters are:
heating to 150-200℃, insulation 60-80min, vacuum degree > 2 x 10-2 pa;
Heating up to 300-400℃, insulation 60-80min, vacuum degree > 8 x 10-3pa;
Heating up to 450-530℃, insulation 40-60min, vacuum degree > 5 x 10-3pa;
Temperature rise to 560-570℃, heat preservation 120-140min, vacuum degree> 4 x 10-3 pa;
Heating up to 615-625℃, insulation 10-20min, vacuum degree > 3 x 10-3pa;
Reduce temperature to 613℃, keep heat for 15-420min, vacuum degree > 3 x 10-3pa;
Cool down to 595-600℃, keep heat for 35-45min, cut off and cool down to 597-600℃.