Which of the six delivery states of stainless steel sanitary pipes do you know?

What kind of stainless steel sanitary pipe delivery status do you know? 1. High-temperature tempering state Steel is subjected to high-temperature tempering heat treatment before leaving the factory. This delivery state is called high-temperature tempering state. The high tempering temperature of high-temperature tempering is conducive to completely eliminating internal stress, improving plasticity and toughness. Carbon structure, alloy steel, and structural steel with guaranteed hardenability can be delivered in high-temperature tempering state. Some martensitic high-strength stainless steels, high-speed tool steels and high-strength alloy steels, due to their high hardenability and the strengthening effect of alloying elements, are often subjected to a high-temperature tempering after quenching (or tempering) to make the steel The medium carbides are properly aggregated to obtain a tempered sorbite structure with coarser carbide particles (similar to the spheroidizing annealing structure). Therefore, the steel in this delivery state has good cutting performance. 2. The hot-rolled steel is no longer subjected to special heat treatment after hot-rolled or forged, and is delivered directly after cooling. It is called hot-rolled or hot-forged. The termination temperature of hot-rolled (forging) is generally 800-900℃. Afterwards, it is generally cooled naturally in the air, so the hot-rolled (forged) state is equivalent to normalizing treatment. The difference is that the end temperature of hot rolling (forging) is high or low, unlike normalizing, which has strict heating temperature control, so the steel structure and properties fluctuate more than normalizing. At present, many steel companies adopt controlled rolling. Due to the strict temperature control of the final rolling and forced cooling measures after the final rolling, the grains of the steel are refined and the delivered steel has higher comprehensive mechanical properties. This is the reason why non-twist controlled cold and hot-rolled wire rod has better performance than ordinary hot-rolled wire rod. Steel delivered in hot-rolled (forged) state has a certain degree of corrosion resistance because the surface is covered with a layer of oxide scale. It is stored and transported. The requirements are not as strict as the steel delivered in the cold drawn (rolled) state. Large and medium-sized steel and medium-thick steel can be stored in the open yard or after being covered. 3. The annealed state stainless steel sanitary pipe is annealed and heat treated before leaving the factory. This delivery state is called annealed state. The purpose of annealing is mainly to eliminate and improve the structural defects and internal stress left by the previous process, and to prepare the organization and performance for the subsequent process, alloy structural steel, structural steel with guaranteed hardenability, cold heading steel, bearing Steels, tool steels, steam turbine blade steels, and iron cable-shaped stainless heat-resistant steels are usually delivered in annealed state. 4. Cold-drawn (rolled) state The state in which the steel materials formed by cold-drawn, cold-rolled, etc., are directly delivered without any heat treatment is called cold-drawn or cold-rolled state. Compared with the hot-rolled (forged) state, the cold-drawn (rolled) state of the steel has high dimensional accuracy, good surface quality, low surface roughness, and higher mechanical properties. Because of the cold-drawn (rolled) state of delivery of the steel The surface is not covered by oxide scale, and there is a large internal stress, which is easily corroded or rusted. Therefore, the packaging, storage and transportation of cold drawn (rolled) steel have strict requirements, and generally need to be kept in a warehouse. And should pay attention to the temperature and humidity control in the warehouse. 5. Solution treatment state Steel is solution treated before leaving the factory. This delivery state is called solution treatment state. This state is mainly suitable for the treatment of austenitic stainless steel sanitary pipes before they leave the factory. Through solution treatment, a single-phase austenite structure is obtained to improve the toughness and plasticity of the steel, create conditions for further cold working (cold rolling or cold drawing), and also prepare the structure for further precipitation hardening. 6. Normalizing state The precision stainless steel pipe is normalized and heat treated before leaving the factory. This delivery state is called normalizing state. Since the normalizing heating temperature (Ac3+30-50°C for hypoeutectoid steel and Accm+30-50°C for hypereutectoid steel) is stricter than the hot rolling termination temperature control, the structure and properties of the steel are uniform. Compared with the annealed steel, due to the faster normalizing cooling rate, the number of pearlite in the steel structure increases, the pearlite layer and the steel grain are refined, so it has higher comprehensive mechanical properties and is helpful for improvement The Widmanstatten structure of low carbon steel and the cementite network of hypereutectoid steel can prepare the structure for further heat treatment of the finished product. Carbon steel and composite steel are often delivered in a normalized state. Certain low-alloy high-strength steels such as 14MnMoVBRE and 14CrMnMoVB steels also require sanitary elbows to be delivered in a normalized state in order to obtain bainite structure.