In order to make better use of standard parts, when we use standard parts, we need to carry out regular maintenance, such as regular cleaning of standard parts, which can improve the efficiency of standard parts.But when we clean standard parts, we often find some problems, mainly six common problems.

　　1. Pollution generated during rinsing

　　After quenching, the standard parts were cleaned with silicate cleaning agent and then rinsed. XX solid matter appeared on the surface. The infrared spectrometer was used to analyze the material and it was confirmed that it was inorganic silicate and iron oxide.This is due to the incomplete rinsing and the residual silicate on the surface of the standard parts.

　　2. Unreasonable stacking of standard parts

　　The standard part shows signs of discoloration after tempering. Soak it with ether and let the ether volatilize and find an oily residue, which is a high content of lipids.It shows that the standard part is contaminated by cleaning agent and quenching oil during the rinsing period, and it melts at the heat treatment temperature, leaving chemical burn scars. Such substances confirm that the surface of the standard part is not clean.For analysis by infrared spectrometer, it is a mixture of base oil and ether in quenching oil.The ether may come from the addition of quenching oil.The analysis results of the quenching oil in the mesh belt furnace confirmed that the standard parts were unreasonably stacked during heating, and the standard parts were slightly oxidized in the quenching oil, but it was almost negligible. This phenomenon is related to the cleaning process, not the problem of the quenching oil. .

　　3. Surface residues

　　There is a white residue on the high-strength screw, which was analyzed by infrared spectrometer and confirmed to be phosphide.No cleaning with acidic detergent was carried out, and inspection of the rinsing tank found that the tank liquid had a higher carbon solubility. The tank liquid should be poured out regularly and the concentration level of the lye in the rinsing tank should be checked frequently.

　　4. Alkali burns

　　High-strength screws are blackened by quenching heat and have a uniform and smooth oil-black outer surface.However, there is an area visible to the naked eye with orange XX in the outer circle.In addition, there are slightly light blue or light red areas.The original bar and wire rod are coated with phosphating film to facilitate cold heading and tapping. They are directly heat treated without rinsing, cooled in quenching oil, washed with alkaline detergent, blow-dried (not rinsed), tempered at 550°C, hot After removing the anti-rust oil from the tempering furnace, red spots were found on the screw threads.

　　It has been tested that the red area on the screw is caused by alkali burns. The chloride-containing substances and calcium-containing compounds of the alkaline cleaning agent will burn the steel standard parts during the heat treatment, leaving marks on the surface of the standard parts.

　　Steel standard parts can not remove surface alkalis in the quenching oil, so that the surface burns in the high-temperature austenite state, and the damage will be aggravated in the next step of tempering.The recommendation is to thoroughly clean and rinse the standard parts before heat treatment to completely remove the alkaline residues that cause the standard parts to burn.

　　5. Improper rinsing

　　For large-size standard parts, polymer aqueous solution quenching is often used, and alkaline cleaning agent is used to clean and rinse before quenching. After quenching, the standard parts have rusted on the inside.Analysis with infrared spectrometer confirmed that in addition to iron oxide, there are sodium, potassium and sulfur, indicating that there is an alkaline cleaning agent inside the standard part, which is likely to be potassium hydroxide, sodium carbonate or similar substances, which promotes its rust.Rinse the standard parts to check whether there is excessive contamination, and it is also recommended to change the rinse water frequently.In addition, adding rust inhibitors to the water is also a good way.

　　6. Excessive corrosion

　　High-strength standard parts often see some black streaks, and we have also seen in the test that the standard parts before heat treatment have been rinsed with inorganic and organic cleaning agents. After quenching, there are still black streaks and even the careful cleaning before heat treatment. Will leave streaks after heat treatment.Infrared spectrometer was used to analyze the residual pollutants on the surface, and it was found that there were higher concentrations of sulfur and calcium.With a small amount of acetic acid and isopropanol, fold a small piece of test filter paper on the dark spot and wipe it firmly, leaving the dark spot on the filter paper.Analyzing the filter paper with infrared spectrometer confirmed that calcium, sulfur, iron, manganese and chromium are the main elements.

　　The presence of calcium and sulfur in the rust spots indicates that this substance is a quenching oil that has been dried out, and it is also the evolution of the gas phase during the quenching process.Because the quenching oil is excessively aging, it is recommended to pour out the old oil, add new oil, and implement process supervision and quenching oil maintenance during the entire process cycle.