The formulation of self-tapping screw performance standards suggests that our manufacturers should follow special standards as the basic standard while formulating self-developed self-tapping screws and self-tapping screw fastener product standards. There are two standards for identifying self-tapping screws and self-locking and anti-loosening screws or whether their performance is good or bad.

Despite the national military standards, only testing methods are provided. One is the national standard, and the military is the national standard. After entering the tempering furnace, iron oxide occurs due to the effect of carbon and temperature, forming a red rust color; The water quenching medium is used for a long time, and the rust prevention in the medium can be reduced to form part rust.

The way to deal with this question, such as pre-treatment before the screw feed into the heat treatment, that is, clean with alkali or acid, and remove the phosphate film on the surface China Concrete Screws factory of the workpiece. After the blackening agent is used for a period of time, usually half a year, the blackening agent must be exchanged throughout the tank. The application temperature should be maintained between 40-50 ℃, and it must be often mixed when not in use to keep the blackening agent in good condition.

The change to abrupt change will eventually damage the application function. For the above questions, the solutions are as follows: Remove the phosphating film; Improve the heating temperature of zone 1 of the mesh belt furnace; When using oil quenching agent, the reasonable temperature should be below 60°C to reduce the aging process of the oil; The control of the carbon potential in the furnace, under the premise of ensuring no decarbonization, reduce the carbon potential as much as possible; Always check the data of water quenching medium, and add rust inhibitor when necessary. 

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