TPT March 2018

AR T I C L E

Shandong Province SiFang Technical Development Co, Ltd

the chemical composition of the forged steel grades directly at casting, which can only result in performance degradation. It should also be noted that the forging material organisation has a strong direction, which causes the material to follow the forging direction as the data shows in Table 2. 3.2 Casting roll The standard selection of the casting roll is an independent intellectual property right created in China. For more than 20 years in China and abroad users have proved the high quality of the finished welded pipe chrome matching the high-grade US, German and Japanese level of forged steel. At the beginning of 2014, SMS Meer, Germany, provided large-scale HFW/ERW high-frequency welded pipe fittings units to Russia, all using high-chrome alloy casting rolls, which were provided by Shandong Province Sifang Technical Development – three sets of spare items with a total of 864 pieces of roll were supplied. The rolls have now been fully installed and are doing an excellent job. The rolls of Shandong Province Sifang have also been exported to Germany, the USA, Russia, Israel, South Africa, South Korea, India and more than 20 other countries. The production of new casting pipe rolls also results in high levels of energy conservation. The casting mould can achieve the final shape and material utilisation using 80 per cent less energy.

Representatives from Germany and Russia visited the workshop to inspect the rolls

3.1.4 Forged steel Cr12MoV, Cr12Mo1V1 This is high quality, high carbon, high chromium cold work die steel. It has a good quench degree, hardenability and wear resistance and is commonly used in the manufacture of large cross-sectional and high precision and complex shapes of the cold mould. China has Cr12Mo1V1 forging supply and it has increased the Cr12Mo1V1. 3.1.5 Forged steel 4Cr5MoSiV1 This is widely used hot work die steel. It is equivalent to the US H13, German X40CrMoV5-1 and Japanese SKD61 steel. It is air-cooled, hardened hot work die steel and has a high thermal strength and heat in medium temperature conditions with good toughness, thermal fatigue properties and a certain wear resistance, as well as high hardenability and hard deformation. 3.1.6 Description The above-mentioned steel grades are forged or rolled and must be put through the forging process to eliminate the segregation, white point and other defects. This makes the organisation even, refined and dense in order to take full advantage of the alloy and to ensure its performance meets its requirements. Weld pipe production and roll production plants should be fully aware of this. It is unreasonable to change

Average value of hardness in depth 30mm from roll surface (HRC)

Average value of hardness in depth 60mm from roll surface (HRC)

Average value of hardness in depth 120mm from roll surface (HRC)

Average value of surface hardness (HRC)

Grade

Condition

D2

Quenching and tempering Quenching and tempering Quenching and tempering Stress release and tempering Quenching and tempering

59.5 58.2 57.7 57.8 60.1

59.6 58.8 57.3 57.4 59.9

59.9 57.9 57.1 57.6 59.5

59.8 57.0 54.6 57.5 59.3

X155CrVMo12-1

SKD11 ZCr20 ZCr15

Table 4: D2, X155CrVMo12-1, SKD11 forging roll and ZCr15, ZCr20 casting roll Hardness drop and depth test result of working layer after dissecting finished rolls

Grade of steel X165CrMoV12

Production country

Heat treatment process

Impact toughness (kJ/m 2 )

Germany

830°C preheat, 1,010°C keep warm, 190°C temper twice 830°C preheat, 1,010°C keep warm, 190°C temper twice

20 37 30 45

Cr12MoV 9Cr2Mo

China

870°C keep warm, 190°C temper once 850°C keep warm, 190°C temper once

GCr15

Table 5: Test results of impact toughness of welded pipe rolls

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MARCH 2018