The chain is an important part of the chain hoist. The quality of the chain also determines the safety of the hoist. The following is a detailed introduction of the distinction between hoist chains.
It is divided into five grades according to quality grade, l / m / p / s / t. Among them, the t8 grade chain with an average stress of 800mp under the action of the minimum breaking force is a lifting chain for chain hoists. T8 short-link chains for hoists require that the T-class lifting load chain be accurately calibrated, and round steel welded short-chain chains must be heat treated. For the material requirements, it should be smelted by electric furnace or oxygen top blowing, and wiped with manganese steel, which has better weldability and cold bendability. The metal grain structure should be at least 5 grades of austenite grain, and the gourd hook part needs to be heat treated, quenched and tempered.
The lifting chain is a high-strength alloy steel chain. According to the strength classification, it can be divided into 50 grades, 60 grades, and 80 grades.
G80 lifting chain commonly used heat treatment methods: annealing, normalizing, quenching, tempering, carburizing, nitriding, carbonitriding, boronizing. The aging treatment includes artificial aging treatment and natural aging treatment. Annealing, heating the workpiece to 30-50 degrees above Ac3, after holding for a certain period of time, slowly cool to 500 degrees in the furnace and cool in the space. Normalizing, heating steel to above Ac3 or Acm, after taking out the heat, take it out of the furnace and cool it in the air. Quenching, heating the steel parts to above Ac3 or Ac1, and rapidly cooling in cooling liquids such as water or oil after holding, has obtained an unstable structure. Tempering, a heat treatment process that reheats the quenched steel to a temperature below Ac1, and cools it to room temperature after holding.