PRODUCT CATEGORIES

Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Benefits of Vacuum Heat Treatment

In the aluminum alloy extrusion process, the extrusion tool and die are the most important production tools that directly determine whether the product can be produced and the quality. Reasonable tool and die design and high-quality production are of great significance to improving the output, quality, production efficiency and yield of extruded products, reducing the consumption of die steel, and reducing production costs. The manufacturing process of aluminum extrusion tools and molds is relatively complex and consists of multiple processes such as billet production, machining, electrical processing, manual polishing and vacuum heat treatment. Vacuum heat treatment is a high-temperature operation performed after the workpiece is cold-processed into a semi-finished product to improve its structure and performance. It is also one of the most critical processes that determines its quality. Because the shape of the tool mold is complex and the thickness difference between various parts is large, the heating temperature and quenching cooling rate need to be strictly controlled to prevent local overburning and cracking.

Aluminum extrusion tool and die vacuum heat treatment equipment operation details

1.The quenching oil temperature before the workpiece enters the oil is ≤ 100 ℃. Fire prevention equipment must be prepared to prevent fire.

2.During the entire process of vacuum heat treatment process operations, operators are required to strictly abide by process procedures and detailed regulations. If problems are found, they should be reported and dealt with in a timely manner, and work will continue only after the problems are resolved.

3.Strictly control the heating speed of vacuum hardening. When the low temperature rises to medium temperature, the speed should be slow. When the medium temperature rises to high temperature, the heating speed should be fast.

4.The workpiece should not be kept in the high-temperature zone for too long. If it is too long, it will cause overheating, coarsen the grains, and reduce the mechanical properties.

5.When heating the tool and mold, strict precautions should be taken to prevent overheating in the high-temperature area to prevent over-burning and scrapping of the entire furnace workpiece.

6.The interval between when the tool and mold comes out of the furnace and enters the oil tank should not be too long and should be controlled at ≤ 3 minutes. If it is > 3 minutes, the workpiece should be pushed back into the vacuum furnace to keep it warm for 10 to 50 minutes (depending on the cooling of the tool and mold). Then lift it out into the oil tank for quenching.

7.In order to ensure that the workpiece is quenched and cooled in the oil tank, it should be moved up and down, left and right to make it cool evenly, and it should be lifted out of the oil tank at the right time (300~500 mm from the oil level), and stay in the air for 1 minute to allow the workpiece to cool down evenly. The heat from the heart is released outward.

8.Large (diameter ≥300 mm) complex workpieces should be quenched and cooled to 180~200 °C in a timely manner in a vacuum tempering furnace for heating and tempering, and are not allowed to stay at room temperature.

9.Small workpieces with simple shapes (diameter ≤ 200 mm mold) are allowed to stay at room temperature after vacuum quenching.

10.After the first vacuum tempering, the tool and mold should be cooled to room temperature of 30~40°C and then vacuum tempered for the second time to ensure the stability of its structure. Check the hardness value after the first vacuum tempering. If it does not meet the technical requirements, the second tempering temperature should be adjusted appropriately.

Calculation and determination of vacuum quenching and tempering holding time for tools and molds

Vacuum quenching, vacuum tempering and holding time. Depends on the furnace type and the effective thickness of the tool mold.

(1) Generally speaking, when the furnace load is large and the furnace heats up quickly, the vacuum quenching and vacuum tempering holding times should be set to the upper limit, and vice versa. The upper limit of the quenching and tempering holding time for large tools and molds with complex shapes is required. (2) Determination of the maximum effective thickness of vacuum quenching. The maximum effective quenching thickness can be determined according to the type and specifications of the tool mold: ① The quenching heating thickness of the flat mold (cake-type parts) is calculated based on the maximum thickness of the mold. ② The upper and lower molds of the flat split flow combination mold are quenched in separate furnaces. The effective heating time of the upper and lower molds should be calculated separately: (a) Calculation of the maximum effective quenching thickness of the upper mold: When the split hole is small, the mold height (excluding core head height) ≤ When the wall thickness (the wall thickness between the diverter hole and the outer circle) is specified, the maximum effective quenching heating thickness is calculated based on the wall thickness. (b) If mold height > wall thickness, the maximum effective quenching heating thickness is calculated based on the height of the upper mold. (c) The maximum effective quenching heating thickness of the lower mold: calculated by subtracting the height of the stop from the height of the mold. ③ Annular parts such as gasket rings and mold supports are calculated according to the following methods: when ϕ outside – ϕ inside: 2 ≤ Η (height), calculate according to H; when ϕ outside – ϕ inside: 2 ≥ Η (height) When , calculate according to ϕOutside – ϕInside ≥ 2. ④ The inner sleeve of the extrusion cylinder is of equal length: on the basis of calculation according to ϕouter – ϕinner 2 (wall thickness), the maximum effective value of (13~12)×(ϕouter – ϕinner) is appropriately increased according to its length. Quenching thickness calculation. ⑤ The extrusion shaft and perforation needle are calculated according to the maximum diameter.