Should we pay attention to these problems in the use of cold heading oil?
February 16, 2023
1. Selection of cold heading oil Cold upsetting oil plays a key role in the fastener manufacturing process. Good cooling performance and extreme pressure and anti-wear performance have made a qualitative leap in the service life of the punch and the improvement of the workpiece accuracy. According to the different material of the workpiece, the performance of the cold heading forming oil is also different when selecting. (1) When selecting the cold heading oil for carbon steel, the better viscosity should be determined according to the process difficulty. It must also be noted that the chlorine type cold heading oil causes rust on the machine and workpiece, and the use of chlorine-free cold heading oil can effectively avoid the problem of rust.
(2) Stainless steel is a material easy to harden. It is required to use cold heading oil with high oil film strength and excellent extreme pressure and wear resistance. Generally, oil products containing sulfur and chlorine compound additives are used to ensure extreme pressure performance while avoiding blackening of workpieces and fracture of punch bars.
2. Reasons for deterioration of cold heading oil (1) At high temperature, the oxidation resistance of cold heading oil deteriorates, which aggravates its thermal decomposition, oxidation and polymerization. At the same time, the dust in the dry air and the moisture in the wet air enter through the air intake system and the crankcase vent to pollute the cold heading oil, so the cold heading oil is easy to deteriorate. (2) The viscosity of lubricating oil changes with the increase of temperature, that is, the viscosity of cold heading oil decreases when it is heated, which is easy to cause the consumption of cold heading oil too fast. (3) At high temperature, the density of cold heading forming oil changes, and the thermal expansion of metal parts is large, and the normal fit gap between parts and dies is smaller, resulting in increased wear of die punches. 3. Test method for cold heading oil (1) Take two measuring cups, one containing the cold heading oil to be inspected, and the other empty on the table top. Slowly pour the full cold heading oil into the empty cup, and observe its flow. The cold heading oil with good quality should flow in a long, thin, uniform and continuous manner. If the oil flow is fast and slow, and sometimes a large block flows down, it is said that the cold heading oil has deteriorated. (2) Twist the cold heading forming oil between the thumb and forefinger for repeated grinding. The better lubricating oil hand feels that it has lubricity, less abrasive debris and no friction. If it feels a large friction feeling such as sand particles between the fingers, it indicates that there are many impurities in the cold heading forming oil and it can't be reused. (3) Observe the condition of oil drops in comparison with the sunlight, and it can be clearly seen that the cold heading forming oil is good and can continue to work if there are no abrasive chips. If there are too many abrasive chips, replace the cold heading forming oil. The above are common problems in the use of cold heading forming oil. Regular inspection and replacement of oil can effectively avoid the occurrence of process quality problems.
