Stainless Steel SS 304 316 Round Bar -Steel Bar

The process flow of the bar production line: steel billet acceptance → heating → rolling → double length cutting → cooling → cutting → inspection → packaging → measurement → storage.

Small bars are produced by small rolling mills, which are mainly divided into continuous, semi continuous, and transverse types. At present, the majority of newly built and in use fully continuous small rolling mills in the world. The current popular steel bar rolling mills include universal high-speed steel bar rolling mills and 4-cut high yield steel bar rolling mills. The billets used in continuous small rolling mills are generally continuous casting small square billets, with a side length of generally 130-160mm, and there are also 180mm x 180mm, with a length of generally 6-12 meters. The unit weight of the billets is 1.5-3 tons. The rolling line is mostly arranged as a replacement for level and grade interchanges, achieving torsion free rolling throughout the entire line.

The number of racks is determined based on the principle of rolling one track per rack. Rolling mills are mostly composed of even number of passes. For small rolling mills with different billet specifications and finished product sizes, there are 18, 20, 22, and even 24 mills, with 18 mills being the mainstream. Adjustable speed, micro tension and tension free rolling are the obvious characteristics of modern fully continuous small rolling mills. The roughing and intermediate rolling sections are controlled by micro tension, while the intermediate rolling sections and finishing rolling units are controlled by non tension to ensure the dimensional accuracy of the products. Continuous rolling mills generally have 6-10 loops, and some even have up to 12 loops. Bar rolling is the easiest variety to achieve among all rolled materials, and it can be done in multiple ways. From the three roll horizontal type to the twisted double type, from various semi continuous to fully continuous types, bars can be produced, but their yield, dimensional accuracy, yield, and qualification rate are all very different. The three roll rolling mill has low stiffness, and the fluctuation of heating temperature will inevitably bring serious product size fluctuations. In addition, the slow horizontal speed and long rolling time lead to an increase in the temperature difference between the head and tail of the rolled piece, making it easy to have inconsistent dimensions and uneven performance. The output is very low, the quality fluctuation is large, and the quality rate is extremely low. The fully continuous rolling mill generally adopts horizontal and vertical alternation, with no twisting of the rolled parts, fewer accidents, and high output, which can achieve large-scale professional production and organizational performance control. At the same time, the rolling mill adopts high stiffness, with a high degree of control automation, which greatly improves dimensional accuracy and qualification rate, especially improves the yield rate and reduces waste in steelmaking. At present, new processes such as stepper heating furnace, high-pressure water descaling, low-temperature rolling, and endless rolling are commonly used in bar rolling. Rough and medium rolling are developing towards adapting to large billets and improving rolling accuracy, while precision rolling machines mainly focus on improving accuracy and speed. Compared with hot rolling of plain carbon steel, the rolling technology and process secrets of stainless steel are mainly reflected in the inspection and cleaning of ingots, heating methods, roll pass design, rolling temperature control, and online heat treatment of products.