1. Delivery status
Delivery status is a commonly used term in steel pipe standards, which refers to the final plastic deformation or final heat treatment status of the delivered steel pipe product. Generally, those delivered without heat treatment are called hot-rolled or cold-drawn (rolled) manufacturing state; those delivered after heat treatment are called heat-treated state, or normalized, quenched and tempered, solution, annealed according to the type of heat treatment. When ordering steel pipes, the delivery status must be indicated in the contract.
(1) Quenching: The process of rapid cooling after heating above the transformation point temperature. Improve the hardness of the material, but reduce the toughness.
(2) Normalizing: After heating above the transformation temperature, cool normally (in air).
(3) Annealing: After heating to above the transformation point temperature, slowly cool. Eliminates quenching effects, eliminates stress, and homogenizes components.
(4) Tempering: After quenching, heat to a certain temperature (below the quenching temperature), keep warm, and then cool. Uniform ingredients, slightly reduced hardness, significantly improve toughness.
Of course, the price of steel pipes is different for different delivery conditions. The more complicated and demanding the delivery status is, the higher the price and the longer the corresponding delivery period.
Usually if there is no special requirement, the steel pipes (seamless pipe
) will be delivered in hot rolled condition.
2. Delivery according to actual weight or delivery according to theoretical weight
Actual weight - at the time of delivery, the weight of its product is delivered according to the weighing (weighing) weight;
Theoretical weight - The weight of the product at the time of delivery is calculated from the nominal size of the steel.