Alloy steel pipe
is suitable for power plant, boiler plant, chemical industry, car, ship accessories, etc. Mechanical property test method: all alloy steel pipes shall be checked for mechanical properties. The mechanical properties inspection methods are divided into two categories: tensile test and hardness test. Tensile test is to make seamless steel pipe into a sample, and pull the sample to fracture in the tensile test machine, and then determine one or more mechanical properties. Generally, only tensile strength, yield strength, elongation after fracture and section shortening rate are generally measured. Hardness test is to slowly press a hard indenter into the surface of the sample according to the regular conditions. And then check the indentation depth or size, so as to recognize the hardness of the material. The cutting ability is outstanding, cold deformation plasticity and weldability are medium. Other steel has little resistance during heat treatment, but alloy steel pipe has proper high strength and abrasion resistance, especially when water quenching. However, the steel has high sensitivity to white point, and temper brittleness and overheating sensitivity are found in heat treatment. Attention to high inspection of seamless steel pipe: the following points shall be paid to the inspection attention of alloy steel pipe: depth and degree of surface decarbonization. The length and depth of the surface rolling defects, shrinkage, the center segregation of carbon and sulfur.
The dispersion of the alloy steel tube and the pearlite are discussed. Other defects of microstructure, such as grain size, surface roughness of seamless pipe and inclusion content, etc. The steel has better function than 30Mn2 steel, with high hardenability, and the critical quenching diameter in water reaches 8-22mm, which is machinability, cold deformation plasticity and weldability. Other steel has low resistance during heat treatment, but it has proper high strength and abrasion resistance, especially when water quenching. However, the steel has high sensitivity to white point and temper brittleness tendency in heat treatment and overheating sensitivity. Alloy steel pipe is mainly used in the condition of tempering, which is used to manufacture hot stamping parts with high resistance and abrasion resistance, and it can also be used in the condition of normalizing or hot rolling supply, such as the track pin of tractor. Steel prices are rising continuously. At the same time, the inventory is down for 7 weeks. The seasonal warming trend is clear.
The Market Demand of Alloy Steel Pipe
In recent domestic steel spot market, building materials, hot rolling, plate plate prices have been rising continuously. The data flash, the price of alloy tube in August rose by about 3% compared with that in July. And the cumulative increase over 5% compared with February. Meanwhile, steel stocks also fell for seven weeks in a row. According to the monitoring, from the total inventory of five major types of wire rod, 27SiMn alloy pipe, hot rolled sheet roll, cold rolled sheet roll and medium thickness plate. By the end of last week, the total inventory of the country was 18.8348 million tons, with a reduction of 138,800 tons, a decrease of 0.74%. This is the seventh week in a row when inventories have fallen. Some industry insiders have indicated that the end of March to April of previous years are significant periods of inventory decline, but the decline rate of this year is not entirely impossible. As a result of the seven consecutive weeks of decline, the total inventory of alloy pipe has only dropped 6.55%, which is a year with a small decline in seventh weeks since 2007. Before that, the concave and convex points that have fallen from the point for seventh consecutive weeks have crossed 14%. And the decline in the same period last year is 15.3%, which is much higher than the decline in this year.
However, the analysis believes that this is due to the fact that the National Day holiday had a certain impact on demand. The situation of the steady decline in store inventory has not changed. The price of alloy pipe has affected the power of steel plant production, and the stock of iron ore port has also been down for 4 weeks, which is the next low level in the year. According to statistics, by September 29, the total iron ore inventory in 30 major ports in China was 96.63 million tons, down 1.39 million tons from the previous week. In September, PMI reached 53.1%, 2.1 percentage points higher than that of last month. During the period, the PMI of steel industry was 49.3%, which is 6.5 percentage points higher than that of last month. Analysts pointed out that the future micro policy measures should be made in demand side, especially capital construction investment. However, the net investment plan for construction in progress at the end of September is up to 35trillion yuan, which