Every customer who has visit us and witness the steel materials before delievry will be impressed by our quality control departemnt. Even not come to inspect the steel materials before delievry, our quality control departemnt will also send inspection report to the customer. For each order, no matter its quantity and value, our quality control departemnt will make strict inspection before delivery, the inspection contents include apperance, tolerance, dimension, mark, special requirements of customers, etc. To guarantee our steel materials sent to the customer is qualified.
Compared with the traditional seamless steel pipe, alloy seamless pipe has better performance in all aspects. Because of the addition of various metal elements in the manufacturing, the overall strength of the alloy seamless pipe is larger, stronger and durable, and the service performance and service life of the S355ML steel, alloy seamless pipe are improved. The alloy seamless pipe is the best choice especially for special environment and high pressure requirements. Because of its high material properties, alloy seamless pipe has good corrosion resistance. It is not easy to be corroded in some special environment, which reduces the cost of the project and has a longer service life.
The chemical composition difference between S355ML steel, Q235B and 20# steel is as follows: The chemical composition of 20# steel: C: 0.17-0.23%, Si: 0.17-0.37%, Mn: 0.35-0.65%, Cr: ≤ 0.25%, Ni: ≤ 0.30%, Cu: ≤ 0.25%. Chemical composition of Q235B steel: C: ≤ 0.20%, Si: ≤ 0.35%, Mn: ≤ 1.40%, P: ≤ 0.045%, S: ≤ 0.045%. The difference of mechanical properties between S355ML steel, Q235B and 20# steel is as follows: The mechanical properties of 20# steel: tensile strength 410 MPa; yield strength 245 MPa; elongation after fracture: 25; reduction of area: 55; no impact. Q235B steel mechanical properties: tensile strength 370-500 Mpa; yield strength: ≥ 235 Mpa; elongation after fracture: 25; impact absorption energy: 27J.
From the order to the delivery, there are three quality inspections to ensure that the qualified rate of finished products is more than 100%. We promise that every order will be tracked in a timely manner to ensure that customers can receive goods safely and constantly listen to their opinions and suggestions, reflect on our own problems, and let customers feel at ease. We have a large warehouse in Shanghai and Tianjin, which can provide customers with sufficient sources of supply.