Vacuum Brazing Furnace for Retarder Cooler

Application of retarder coolers in a vacuum brazing furnace

2025-12-26 17:40

What is a Retarder Cooler?

A retarder cooler, typically referring to a hydraulic retarder cooler, is a heat exchange device installed on heavy trucks, buses, or construction machinery. Its primary function is to transfer the immense heat generated by the hydraulic retarder during braking to the vehicle’s engine cooling system (water circuit), thereby preventing the retarder from overheating and failing.

It is usually made of aluminum alloy (such as AL3003) or stainless steel, as these materials have good thermal conductivity and corrosion resistance.

Manufacturing Process: Vacuum Brazing

The following is the specific process for manufacturing a retarder cooler in a SIMUWU vacuum brazing furnace, using AL3003 as the base material and AL4104 as the brazing filler metal：

1. Initial Heating and Degassing:

The temperature is raised from room temperature to 350-400℃, with a heating time of approximately 20-40 minutes, to remove residual gases in the furnace and adsorbed moisture from the workpiece surface.

2. Preheating:

The temperature is maintained at 400℃ for approximately 40-60 minutes to relieve thermal stress and ensure uniform temperature throughout the workpiece, preventing deformation.

3. Heating:

The temperature is raised from 400℃ to 500-560℃, with a heating time of approximately 30-50 minutes. The key point of this step is that the magnesium in AL4104 begins to evaporate significantly at this stage, damaging the oxide film.

4. Brazing and Holding:

The temperature is held at approximately 600℃ for about 8 minutes. The solder melts to form a weld seam. The holding time should not be too long, otherwise erosion will occur.

5. Cooling:

The temperature is lowered from the highest temperature to below 500℃ to rapidly solidify the weld seam and reduce grain boundary embrittlement.

The following are the specific technical parameters of the vacuum brazing furnace required for vacuum brazing of AL3003:

SIMUWU Vacuum Brazing Furnace Specifications

Furnace design	Horizontal type,front and rear door opening
Working zone size	700(W) x 700(H) x 1000(L)mm
Loading capacity	800kg (with fixture and jigs)
Power supply	380V (3 phase)/50HZ
Heating power	100 KW
Installed power	150 KW
Max.design temperature	750℃
Working temperature	RT(Room Temperature)-700℃
Temperature control accuracy	±1℃(Vacuum，Empty, 600℃)±1℃
Temperature uniformity	±5℃, 9 points temp testing±5℃
Temperature control components	PLC
Thermal couple	“K” Type
Heating rate	0-20℃/ min
Ultimate vacuum degree (drying&degassing )	6.7×10-4Pa
Working vacuum degree	6.7×10-3Pa
Pressure rising rate	≤0.5Pa/h
Temperature control	PLC
Control mode	PLC Automatic/manual interlock protectionPLC
Equipment color	Customized (user provide RAL color number)