Tube rolling mill of seamless steel pipe

Capillary rolling is the main deformation process of seamless steel pipe production. Its function is to make the wall thickness of the capillary close to or reach the thickness of the finished pipe wall, and to eliminate the uneven thickness of the longitudinal wall produced by the capillary during the perforation process. The surface quality of the inner and outer parts of the waste pipe, controlling the outer diameter and roundness of the waste pipe. The hollow capillary tube is rolled into a waste tube that is close to the finished size.

1. Automatic pipe rolling machine: The automatic pipe rolling machine is a two-roller irreversible vertical rolling mill. It is characterized in that a pair of high-speed reverse-rotating return rolls are arranged behind the work rolls, and the function is to send the once-rolled capillary tubes to the front. The second rolling is carried out, so its production efficiency is low, and most of the domestic units have been modified or eliminated. The material of the rolls is mostly infinite chilled cast iron, ductile iron or chilled ductile iron, and the hardness is above HSD50.

2, Two-roll continuous rolling mill: continuous rolling mill is a more advanced steel tube rolling mill, it is to put the perforated capillary on the long core rod, arranged in multiple racks in sequence and the adjacent rack roll gap is 90°. The continuous tube mill is rolled. The material of the continuous roll is mostly nickel-chromium-molybdenum infinite chilled ductile iron (also known as pearlitic ductile iron), nickel-molybdenum infinite chilled ductile iron (also called needle-shaped ductile iron), and the hardness of the hole type is HSD50-65. The first frame of the continuous roll designed abroad is made of forged steel or graphite steel to further increase the strength of the roll.

3. Three-roll continuous rolling mill: The three-roller adjustable limit mandrel mill (PQF) was developed by INNSE Italy to overcome the inherent limitations of the two-roll mill, since it will be 360°. The type is divided into three parts, which reduces the line speed difference between the bottom and the edge of each roll hole type, so the rolled steel pipe has high precision. The continuous roll of the small PQF rolling mill is monolithic. Nickel-chromium-molybdenum infinite chilled ductile iron is used. The hardness is controlled at HSD55-65. The continuous rolls of large PQF rolling mills are assembled, that is, the rolls are wear-resistant. It is better to use nickel-chromium-molybdenum infinite chilled ductile iron. The shaft is made of high-strength forged steel material, which can be reused after quenching and tempering, which greatly saves the cost. This structure has been successfully used in Tianjin Pipe Company.

4. Assel rolling mill: Assel rolling mill is three-roll cross-rolling, which consists of three active rolls and one core rod. The roll is divided into four sections: inlet cone, roller shoulder, flat zone and outlet cone. The material is made of 4Cr5MoSiV1 forged steel, cast semi-steel or alloy ductile iron. Heat treatment hardness: forged steel roll is controlled at HSD65-75, semi-steel roll is controlled at HSD50 —60, alloy ductile iron roll is controlled in HSD55—65 (this kind of material roll is designed for imported units, and there are few successful application examples in China).