Advantages in high-speed steel roll materials

• The high-speed steel roll material contains high alloy elements such as vanadium, tungsten, chromium, molybdenum, niobium, etc. The types of carbides in the roll structure are mainly MC type and M2C type. Compared with ductile iron rolls and high-nickel-chromium rolls, the single-groove (time) steel passing is higher, which saves roll changing time, improves rolling mill operation rate, reduces roll consumption, reduces production costs, and improves the overall benefit of the factory.
• The high-speed steel roll material has a large expansion coefficient and good thermal conductivity. While the roll wears a small amount of the groove during the rolling process, due to the expansion of the high-speed steel material itself, the hole shape continues to become smaller. Therefore, the high-speed steel roll is rolling. During the process, the change of the rolling groove is small, and the consistency of the pass size is maintained for a long time, especially when rolling bars or rebars, it is more conducive to control the negative tolerance of the rolling material.
• Centrifugal casting high speed steel roll core is made of alloy ductile iron material, so the roll neck strength is high

The following table shows the types and microhardness of alloy carbides formed by different material rolls.

Advantages of the metallographic structure of high-speed steel rolls

It can be seen from the metallographic photos that the metallographic structure of the high-speed steel roll is much better than other materials in terms of the shape, quantity, size and distribution of carbides, as well as the matrix structure and grain size.

Advantages in the use of high-speed steel rolls

During the use of high-speed steel rolls, under good cooling conditions, a thin and dense oxide film is formed on the surface of the roll body. This uniform, thin and dense oxide film can exist for a long time without falling off, so that the wear resistance of the high-speed steel roll is significantly improved.

Other main advantages of high-speed steel rolls

• High-speed steel rolls have good thermal stability, and the roll surface has high hardness and good wear resistance at rolling temperature.
• The high-speed steel roll has good hardenability, and the hardness from the surface of the roll body to the inside of the working layer hardly decreases, thus ensuring that the roll has the same good wear resistance from the outside to the inside.

Product design→ Roll blank design→ Roll blank manufacturing→ Roll blank acceptance→ Annealing→ Rough turning→ Ultrasonic flaw detection→ High temperature quenching→ Low temperature tempering→ Ultrasonic flaw detection→ Finishing→ Ultrasonic flaw detection→ Roll body grinding→ Roll numbering→ Inspection→ Cleaning → Packing → Shipping → Warehousing → Inspection → Use and Maintenance → On-site Communication → Design Improvement.

As can be seen from the flow chart, roll manufacturing forms a closed-loop system from product design, production and manufacturing, use and maintenance, and improved design, and the quality of rolls is constantly improving.

• Testing standards

The manufacture and inspection of high-speed steel roll products are strictly in accordance with the relevant requirements of national standards such as GB/T 13313-2008 “Roll Shore and Leeb Hardness Test Methods” and GB/T 1503-2008 “Cast Steel Rolls”.

Testing regulations:

1. Check the size and surface quality of each part one by one;
2. Carry out ultrasonic flaw detection three times one by one;
3. Carry out hardness test piece by piece;
4. The depth of the hardened layer of the roll body is affected by the manufacturing process.