Coupe for gripping sample slipping treatment of tensile testing machineThe tensile testing machine can detect many standards of materials, and different materials are tested in various tests, and different fixtures are needed to cooperate. There are some problems in the daily use of tensile testing machine fixtures. The slipping problem is one of them. How to deal with this kind of slipping problem? There are several methods:
Method 1, standard operating procedures
In view of the short clamping length of the specimen and improper selection of the jaws of the clamp, the operating rules of the electronic tensile testing machine must stipulate: "The clamping length of the tensile specimen shall not be less than the length of the tooth surface of the clamp" and "No Use jaws for large cross-sections to clamp small cross-section specimens or use flat chucks to clamp large specimens", the operator must carry out the test in accordance with the operating procedures.
Method 2. Repair the wedge-shaped inclined surface
If the wedge block is plastically deformed, severely turned outward, and the inclined surface of the wedge block is collapsed or worn, it should be repaired in time. Generally, the following methods can be used for repairing
The inclined surface of the wedge block is removed by a slotting machine at the original design angle by 10 mm, and then a polished quenched steel plate is inserted in this part. This method slightly weakens the design strength of the fixture body, but the long-term use effect is better.
B. Repair welding
The collapsed or worn part of the wedge block slope should be repaired first, and then restored with a slotting machine (if the machining fails to meet the roughness requirements, it should be scraped). The hardness and strength of the repair welding part will generally be improved, and it is enough to pay attention to the correct use of the fixture in the future.
C. Anti-layering device
In order to prevent the iron oxide scale from falling into the inclined surface of the wedge block during the stretching process, two rubber blocks can be installed on the top of the wedge, which can effectively reduce the iron oxide scale falling into the inclined surface. In addition, butter can be applied to the inclined surface of the wedge block. Or grease, and regularly scrub the fixture and change the oil.