Introduction to S275NL American Standard Boiler Vessel Plate
S275NL steel plate is a European standard alloy steel plate, which implements EN10025 standard. The difference between S275NL steel plate and S275N is that the impact temperature and impact energy are different. S275N stands for -20°C impact, and S275NL steel plate steel plate reaches -50°C impact.
| Chemical composition |
| Tabulation: Depu Steel Date: 2024-01-18 |
| C |
Si |
|
Mn |
P |
S |
N |
Al |
Cr |
| ≤0.16 |
≤0.40 |
0.5-1.40 |
≤0.030 |
≤0.025 |
≤0.015 |
≥0.020 |
≤0.030 |
Note:
S275NL steel requires the delivery state to be normalized state + level II flaw detection, that is, after normalizing treatment, the ultrasonic detection of the steel plate is required to be free of inclusions and cracks. This variety also puts forward higher requirements for the stretching of steel plates with a thickness of more than 40mm in the thickness direction.
With the rapid development of the wind power industry, the demand for high-toughness wind power steel is growing rapidly. At present, in order to improve the comprehensive mechanical properties of high-toughness wind power steel, steel mills generally adopt refining and microalloying processes in smelting, and control rolling (cooling) process in steel rolling to control the grain size of steel, so as to obtain high toughness of materials. However, for the 85mm thick S275NL high-toughness wind power steel, which requires a low-temperature impact toughness of -50°C, the microstructure obtained by only the controlled rolling (controlled cooling) process is usually uneven, the strip structure is serious, and the ferrite and pearlite are distributed in layers along the rolling direction. The strip structure makes the mechanical properties of the steel plate anisotropic and reduces its plasticity and toughness. In order to eliminate the strip structure and improve the comprehensive mechanical properties of S275NL high-toughness wind power steel, the effect of normalizing process on the microstructure and properties of S275NL high-toughness wind power steel was studied, and the main factors influencing the physical properties during normalizing process were identified, and a reasonable normalizing process was formulated.
S275NL container plate production process:
electric furnace smelting→LF/VD furnace refining→ ingot → ingot cleaning→ ingot heating→ rolling plate → flaw detection→ normalizing → steel plate grinding→ cutting and sampling→ performance inspection → warehousing
