A kind of fin steel with excellent surface quality and its csp production process

Abstract

Fin steel excellent in surface quality comprises no more than 0.01wt% of C, 0.18-0.30wt% of Mn, 0-0.02wt% of Si, no more than 0.005wt% of Als, 0-0.03wt% of P, 0-0.01wt% of S, and 0.002-0.007wt% of N. A technology of the fin steel comprises the steps that converter smelting is conducted; LF refining is conducted; a casting blank enters a soaking furnace for soaking; scale is removed with high-pressure water; before rolling of machine frames, roll gap cooling water is started, then, a seven-machine-frame unit is adopted for finish rolling; laminar cooling is conducted; and reeling is conducted. According to the fin steel excellent in surface quality and the technology, the defects that fin steel has too much scale, and roll marks occur due to the fact that the head and the tail of belt steel impact a reeling and clamping roll in the tension lost state are overcome, the advantages of the short technological process are sufficiently achieved, the thickness precision of a whole produced steel reel fluctuates within 30 [mu]m, and the strength of the whole steel reel in the length direction fluctuates within 20 Mpa.

Description

technical field [0001] The invention relates to an ultra-low carbon steel and its CSP production process, in particular to a fin steel with excellent surface quality and its CSP production process. Background technique [0002] Fin steel is the raw material for fin heat exchangers. As a kind of heat exchange device, the finned heat exchanger is named after its heat exchange unit looks like a fin. It is mainly used for air heating in the drying system and is the main equipment in the hot air device. The heat medium can be steam or hot water, and heat transfer oil can also be used. Because of the mechanical winding, the contact surface between the heat dissipation fin and the heat dissipation pipe is large and tight, the heat transfer performance is good and stable, the air passage is small, and the heat exchange efficiency is high. Due to the demand for energy saving and environmental protection, the output of fin steel has grown steadily in China in recent years. Fin steel...

AI Technical Summary

Problems solved by technology

The traditional thick slab and conventional hot rolling production line are used for production, and its shortcomings are: (1) The product thickness accuracy is low: the subsequent process of fin steel is pickling, slitting, and compound rolling, and the customer requires slitting Afterwards, the transverse and longitudinal thickness differences are not more than 30 μm, so the thickness accuracy of hot-rolled raw coils is highly required. It is required that the convexity shall not exceed 50 μm, the wedge shape shall not exceed 20 μm, and the longitudinal thickness difference must be controlled within 30 μm. Conventional hot-rolled production lines It is difficult to fully satisfy; (2) The uniformity of product performance is poor: during compound rolling, the full-length rolling load fluctuation is required to be small, and the full-length strength fluctuation of the hot-rolled raw material coil is required to be within 30MPa, while the conventional hot-rolled production line is required The reason is that there is a certain deviation in the temperature between the head and tail of the strip and the middle part, so the performance of the entire length fluctuates greatly; (3) There are edge warping defects: when the conventional hot rolling production line is produced, there is an edge within 15-30mm from the edge. Part warped skin defects, on the one hand, the yield rate is low, on the other hand, it also causes more quality complaints and compensation; (4) Long production cycle: from the contract to the delivery of steel coils, it generally takes 1 month , for contracts with urgent delivery deadlines, it is difficult to deliver in time to meet customer requirements

However, when using the CSP process to produce fin steel, there are the following deficiencies: (1) Scale defects: the heating method and rolling process of the soaking furnace of the CSP production line are different from the conventional hot rolling production line, and the phosphorus removal equipment capacity is not as good as the conventional one. Hot rolling production line, scale defect control has always been the weak link of thin slab continuous casting and rolling process

On the one hand, it affects the pickling surface quality of finned steel; on the other hand, on the CSP surface quality detector, many defect frames are formed, which affects the inspection and identification of other defects such as inclusions and oil stains, and easily leads to missed judgments of defects and corresponding quality problems. objection

(2) Coiler pinch roller print defects: due to the softness of the fin steel, the strip head is easy to hit the coiler pinch roller when it is coiled at high speed, resulting in small peeling off of the strip head Fragments, etc. adhere to the surface of the feed roll, and are pressed into the surface of the strip during the subsequent coiling process, forming roll mark defects

[0005] After searching, the above-mentioned surface quality problems rarely exist in the current conventional hot rolling production line, especially the roll printing defects of the coiling and pinch rolls.

However, similar CSP production lines have no experience in producing similar fin steel, and there is no solution that can be used for reference.

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