Defects and preventive measures caused by heat treatment of silicon steel sheet punching and punching dies using ultrasonic induction heating equipment

Silicon steel sheet punching and punching dies are required to have high wear resistance and high hardness due to the limitations of their working conditions. In order to meet this, we usually use ultrasonic induction heating equipment to perform simple heat treatment. However, during the heat treatment process, some defects will inevitably occur. Today, I will tell you the preventive measures for these defects.

1. Blade wear is caused by insufficient hardness, low heating temperature or short heating time. We should use intermediate or high temperature tempering and ensure that the hardness is above 60HRC to improve wear resistance.

2. It is brittle and breaks. The causes and preventive measures are as follows:

(1) The tempering specification is incorrect, resulting in insufficient tempering and reduced toughness. We should standardize the tempering operation and perform sufficient tempering.

(2) The quenching temperature is too high or the holding time is too long, forming a coarse martensite structure. We should strictly implement the prescribed heat treatment process and inspect the metallographic structure.

3. Cracks. Cracks are a common defect in workpieces during heat treatment. We should pay special attention to them. The causes and preventive measures are as follows:

(1) Improper grinding results in superposition of quenching and stress on the mold surface. We should improve the grinding amount and ensure sufficient cooling effect.

(2) There are cracks in the raw materials. If it is folded or has serious mesh or ribbon carbides, we should conduct flaw detection on the material or eliminate mesh or ribbon carbides.

(3) There is a large machining stress in steel. We should preheat or precool the workpiece before quenching.

(4) Improper heat treatment operation (too fast heating or cooling, improper selection of quenching medium, too low cooling temperature, etc.), failure to temper in time or insufficient tempering after quenching, and secondary quenching without annealing, we should perform it according to the process requirements operate.

4. Cracking and brittle fracture or partial peeling of the cutting edge. The causes and preventive measures are as follows:

(1) The carbides have poor unevenness and are relatively concentrated in distribution. We should forge the workpiece, crush the carbides and anneal them.

(2) High hardness or insufficient tempering causes the mold to be brittle. We should strictly implement the correct heat treatment process specifications and conduct inspections.

5. Causes and preventive measures of insufficient hardness:

(1) If the tempering temperature is too high, the tempered martensite will decompose and aggregate. We should strictly implement the correct heat treatment process specifications, reduce the tempering temperature, and make the tempering temperature appropriate.

(2) The heat treatment process is not standardized. There is residual decarburization layer on the surface, excessive residual austenite is formed, insufficient tempering, insufficient heating or insufficient cooling time. We should strictly implement the relevant heat treatment process requirements and carry out process parameters. Proper design, etc. to avoid heating or cooling defects.

6. Overheating or overburning, causes and preventive measures:

(1) The quenching temperature is too high or the holding time is too long. We need to strictly control the quenching temperature and holding time.

(2) If the workpiece is placed improperly, close to the electrode or heater, we should install the furnace reasonably to ensure the consistency of the temperature in the furnace within the effective heating zone.

(3) The spheroidization structure is poor, and we should correctly implement the annealing process specifications.

Today we will introduce the defects caused by heat treatment of silicon steel sheet punching and punching dies. Zhengzhou Gou's is a manufacturer specializing in ultrasonic induction heating equipment. The equipment it produces has complete functions and simple operation, and has been well received by users. If you would like more detailed information please call us.