1、 Causes of stress cracking of products
The products with residual internal stress are affected by solvent, oil and medicine.
2、 Associated knowledge
1. The same reason as deformation and crack.
2. We consider that the stress cracking may be due to the effect of solvent, oil and drug to reduce the binding force of products
3. The detection of stress cracking only needs external force. The simple way is to hang under the tested products
Load the heavy object to make the stress of 20% of the tensile strength occur. At this time, coat it with solvent, oil and medicine for one week
4. Because the actual type of drug is a mixture, it cannot be generalized. Due to a small amount of antirust oil or
The effect of cutting oil will produce cracking effect.
5. In the experiment, all the solvents, Oils and drugs have more or less influence on the products, so
Containers used must be carefully inspected and cleaned in advance, and no foreign matters are allowed.
1. Instant: degrease die parts and screws installed after heat treatment.
2. Long term: change the material into crack resistant material.
4、 Due to material differences
1. The GP value of polyaniline is the weakest, followed by hi. As and ABS are relatively strong.
2. Polyethylene (PE) is weak for specific solvents, while polypropylene (PP) is very strong.
1. The products without residual stress can be obtained by forming conditions, that is to say, the products can be obtained by micro control of forming conditions
To no residual stress is impossible in reality.
2. It should be noted that when the drug resistance data is high, it is under the condition of no stress of the product and under the situation of stress
There are significant differences in the effects.
3. Stress cracking can be measured by residual stress, and residual stress can be detected by immersion in kerosene in polystyrene
Location of residual stress