CN102296231B - Method for producing 0.25-0.35mm superfinishing cold-rolled sheet by continuous annealing line - Google Patents

Abstract

The invention provides a method for producing a 0.25-0.35mm superfinishing cold-rolled sheet by a continuous annealing line. The 0.25-0.35mm superfinishing cold-rolled sheet comprises the following chemical components: 0.06-0.08 percent of C, not more than 0.03 percent of Si, 0.25-0.35 percent of Mn, not more than 0.015 percent of P, not more than 0.012 percent of S, 0.01-0.05 percent of Als and not more than 0.006 percent of N. Through controlling walking speed of strip steel in a continuous annealing furnace and adopting rolling of a smooth roll with a lower annealing temperature and a roughness of 0.3-0.4 micrometer, the smooth percentage elongation is controlled to be between 0.25 percent and 0.40 percent, thus the qualified 0.25-0.35mm superfinishing cold-rolled sheets can be produced by adopting a large vertical continuous annealing line, and have an average tensile strength of reaching 347MPa and a percentage elongation after fracture of 45.5 percent, thus conditions of unqualified slabs are avoided, imperfect and waste products are reduced remarkably; and compared with the 0.25-0.35mm superfinishing cold-rolled sheet produced by adopting a bell-type furnace, the 0.25-0.35mm superfinishing cold-rolled sheet produced by adopting large vertical continuous annealing line has the yield of being increased by above 7 percent.

Description

A kind of continuous annealing unit is produced the method for 0.25-0.35mm ultraphotic cold-reduced sheet

Technical field

The invention belongs to the cold-rolling process field, be specifically related to a kind of method of utilizing the cold rolled continuous annealing unit to produce the thinner cold rolled strip of ultraphotic.

Background technology

The cold rolling panel of ultraphotic mainly is to use in the products such as auto parts and jewellery, and its thickness requires steel surface roughness below 0.6 μ m, and visual visual defects can not be arranged generally at 0.25～0.5mm.Although the user takes itemize to use more, and is less demanding to plate shape; But the cold rolling panel effects on surface of ultraphotic is had relatively high expectations, because supplied materials smooth surface, when producing, very easily cause by continuous annealing furnace the band steel to skid, make the surface quality of ultraphotic panel not reach on the contrary the effect that bell furnace is produced, therefore this ultraphotic panel all adopts batch annealing production generally speaking.

In the batch annealing production process, exist inevitably bonding, heat to press against the defectives such as wound, and so thin with steel rolling time Mo rolling mill must adopt the smooth roll of utmost point low roughness rolling, make plate shape extremely be difficult to control.And plate shape is bad behind the belt steel rolling, after the process cover annealing, unrelieved stress is released in the band steel, during through smooth unit, the control of plate shape is more difficult, often cause the plate shape claimed range that is above standard, have to take again smooth to the band steel, the measures such as aligning come Repair, not only waste time and energy, and still have major part can't satisfy user's service requirements with steel after processing, and cause the lumber recovery of ultraphotic panel to be paced up and down 85% always, the cold rolling panel of ultraphotic is rolling in addition, hourly capacity when smooth is very low, thereby it is low directly to cause bell furnace to produce ultraphotic panel lumber recovery, the ill effect that production efficiency is low, both wasted energy, affected again output, and caused a large amount of residual, inferior, waste product, increase production cost, reduced economic return.

Summary of the invention

Purpose of the present invention is exactly for defects, provides a kind of large-scale vertical continuous annealing furnace that utilizes to produce the cold rolling ultraphotic panel of 0.25-0.35mm, and can increase substantially the method for kind lumber recovery.

For this reason, the technical solution taked of the present invention is:

A kind of continuous annealing unit is produced the method for 0.25-0.35mm ultraphotic cold-reduced sheet, and its material chemical component weight percent content is:

C0.06～0.08, Si≤0.03, Mn 0.25～0.35, P≤0.015, S≤0.012, Als 0.01～0.05, N≤0.006, remaining is Fe and impurity;

The cold-rolled compression ratio is 83.3～85%;

Between 220～240m/min, annealing temperature is controlled at above 50～80 ℃ of recrystallization temperature with the traveling speed of steel in continuous annealing furnace;

Polishing machine working roll roughness is 0.3～0.4 μ m, and smooth elongation control is 0.25～0.40%, and the polishing rolling load is controlled at 300～400t.

Adopt the present invention's method to realize the cold rolling ultraphotic panel of large-scale vertical continuous annealing unit production 0.25-0.35mm, and its yield strength and tensile strength are all than adopting usual way production to exceed 20～40MPa, average tensile strength reaches 347MPa, and elongation after fracture is 45.5%.Especially pass through the annealing of large-scale vertical continuous annealing furnace and the rectification of furnace roller, avoided the underproof situation of plate shape, obviously reduced residual, inferior, waste product, compare with bell furnace production, its kind lumber recovery has improved more than 7%, has increased the economic return of enterprise.

Embodiment

Embodiment 1:

Slab thickness 1.9mm produces 0.25mm ultraphotic panel.

The material chemical component weight percent content is:

C0.06, Si0.028, Mn0.34, P0.012, S0.010, Als0.015, N0.005, remaining is Fe and impurity;

Should not be too high with the traveling speed of steel in continuous annealing furnace, but can not be excessively low.Traveling speed is too high, and tension force is unstable, and the stability of production also decreases, and degree-of-difficulty factor is corresponding to be increased; Traveling speed is excessively low, and then annealing time prolongs, can cause being with hardness of steel significantly to descend, and the steel deliquescing, and easily produce wrinkle defect, therefore be controlled at 235m/min with the traveling speed of steel in continuous annealing furnace.

Generally speaking, the annealing temperature of common CQ steel is 760 ℃.But because the very thin thickness of the 0.25mm ultraphotic panel that will produce, cold-rolled compression is larger than again, so annealing temperature needs suitably to reduce.Consider the recrystallization temperature of common CQ steel about 650 ℃, therefore the selective annealing temperature is at 710 ℃.

Adopt 84.2% larger cold-rolled compression ratio, rolling rear finished strip thickness is that 0.3mm, width are 950mm.

According to standard and customer requirements, polishing machine selection working roll roughness is that the smooth roll of 0.3 μ m is rolling, and for safety, its polishing rolling load is controlled at 330t.

Because annealing temperature is relatively low, though that the metal recrystallize can carry out is abundant fully not, therefore adopt lower smooth unit elongation, smooth elongation control is got final product 0.4%.

Embodiment 2:

Slab thickness 2.0mm produces 0.32mm ultraphotic panel

Raw material control composition weight percent content is:

C0.08, Si0.02, Mn0.25, P0.010, S0.008, Als0.05, N0.0045, remaining is Fe and impurity;

Be controlled at 235m/min with the traveling speed of steel in continuous annealing furnace;

Annealing temperature is at 730 ℃;

Adopt 85% larger cold-rolled compression ratio, rolling rear finished strip thickness is that 0.3mm, width are 950mm.

Polishing employing roughness is that the smooth roll of 0.5 μ m is rolling, and rolling load is controlled at 390t;

Satisfying under the prerequisite of performance, adopting 0.28% smooth unit elongation.

Claims (1)

1. a continuous annealing unit is produced the method for 0.25-0.35mm ultraphotic cold-reduced sheet, its material chemical component and weight percent content are: C0.06～0.08, Si≤0.03, Mn0.25～0.35, P≤0.015, S≤0.012, Als0.01～0.05, N≤0.006, and remaining is Fe and impurity; It is characterized in that,

The cold-rolled compression ratio is 83.3～85%;

Between 220～240m/min, annealing temperature is controlled at above 50～80 ℃ of recrystallization temperature with the traveling speed of steel in continuous annealing furnace;

Polishing machine working roll roughness is 0.3～0.4 μ m, and smooth elongation control is 0.25～0.40%, and the polishing rolling load is controlled at 300～400t.