What are the welding precautions for S420ML material number

The S420ML material number plate products have passed the EU CE certification, and have been recognized by China, France, the United States, the United Kingdom, Germany, Italy, Japan, South Korea and other eight classification societies for high-strength ship plates. The steel strand products have passed the United States (PTI) certification. The S420ML material number products enjoy a high reputation in the domestic and foreign markets. The products are applied to national key projects and sold to 37 countries and regions such as EU, Middle East, Southeast Asia and America.

As a pipeline of oil and natural gas, spiral pipe has its own characteristics: 1. The amount of use is large, because the specifications of S420ML material number, spiral pipe used in a project are often diversified. During the forming process of the spiral pipe, the steel plate deforms evenly, the residual stress is small, and the surface does not occure scratches. 2. The spiral pipe is used in a complex environment, and the quality must be guaranteed, otherwise it will delay the follow-up project progress.

15CrMo alloy steel plate is pearlite structure heat-resistant steel, which has high heat strength (δb≥440MPa) and oxidation resistance at high temperature, and has certain resistance to hydrogen corrosion. Due to the high content of Cr, C and other alloying elements in steel, the hardening tendency of steel S420ML material number is obvious and the weldability is poor. 15crmo alloy steel plate is mainly used in petroleum, petrochemical, high-pressure boilers, etc.

Hydrogen (H) is the most harmful element in general steel such as S420ML material number. Hydrogen dissolved in steel will cause hydrogen embrittlement, white spots and other defects. Hydrogen, like oxygen and nitrogen, has very little solubility in solid steel. It dissolves into liquid steel at high temperature, and accumulates in the structure without time to escape when cooling, forming high-pressure micro pores, which greatly reduce the plasticity, toughness and fatigue strength of steel, and even cause cracks and brittle fracture in severe cases. "Hydrogen embrittlement" mainly occurs in martensitic steel, but not very prominent in ferrite steel, and generally increases with hardness and carbon content.

S420ML material number, Q690 steel is low alloy high strength steel. It belongs to the Chinese GB standard steel. Q690 steel is named after its yield strength value. Q is the abbreviation of yield strength, that is, the yield strength of Q690 steel is 690 MPa. Chemical composition of Q690 steel: C ≤ 0.18, Si ≤ 0.60, Mn ≤ 2.0, P ≤ 0.030, S ≤ 0.025, Nb ≤ 0.11, V ≤ 0.12, Ti ≤ 0.20, Cr ≤ 1.00, Ni ≤ 0.80, Cu ≤ 0.80, N ≤ 0.015, Mo ≤ 0.30, B ≤ 0.004, Al ≤ 0.015. The mechanical properties of Q690 steel are: yield strength ≥ 690 MPa, tensile strength 730-940 MPa, elongation after fracture ≥ 14%, impact energy 31J.

SG255 gas cylinder S420ML material number steel is widely used in petroleum, chemical industry, power station, boiler, etc, used to make the reactor, heat exchanger, separator. The company is a professional gas cylinder steel exporter and a steel stockist in china. We keep more than 1000 tons SG255 gas cylinder steel coils in S420ML material number stock every month. If you want to get the steel price, please do not hesitate to contact us. Any need in SG255 Chemical Composition and Mechanical Properties, please feel free to contact us by email or calling to us.

After-sales service team is a key department to test the steel quality. Product quality is always the foundation of our survival and development. The company's full inspection from raw materials to finished products; and implements standardized, scientific, and strict internal quality control and management systems in accordance with the process flow during the production process; products can only leave the factory if qualified, and follow-up problem solving systems are implemented in after-sales services to guarantee the customers’ interest.