CN102296231A - Method for producing 0.25-0.35mm super-bright cold-rolled sheet by continuous annealing unit - Google Patents

Abstract

The invention provides a method for producing 0.25-0.35mm super-bright cold-rolled sheet by a continuous annealing unit, which comprises the following chemical components: 0.06-0.08 percent of C, less than or equal to 0.03 percent of Si, 0.25-0.35 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.012 percent of S, 0.01-0.05 percent of AlsN and less than or equal to 0.006 percent of N, the flat elongation is controlled between 0.25-0.40 percent by controlling the traveling speed of the strip steel in a continuous annealing furnace and adopting a smooth roll with lower annealing temperature and 0.3-0.4 mu m of roughness to roll, so that the large vertical continuous annealing unit can produce a cold-rolled ultra-smooth panel with the thickness of 0.25-0.35mm in a qualified way, the average tensile strength reaches 347MPa, the elongation after fracture is 45.5 percent, the condition that the plate shape is unqualified is avoided, the residue, secondary and waste products are obviously reduced, and the variety yield can be improved by more than 7 percent compared.

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 thin cold rolled strip of ultraphotic.

Background technology

The cold rolling panel of ultraphotic mainly is to use in 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.Though the user takes itemize to use more, and is less demanding to plate shape; But the cold rolling panel of ultraphotic is had relatively high expectations to the surface, 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 the effect that bell furnace is produced on the contrary, therefore this generally speaking ultraphotic panel all adopts batch annealing production.

In the batch annealing production process, exist bonding, heat to press against defectives such as wound inevitably, and so thin band 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 difficulty more, often cause the plate shape claimed range that is above standard, have to take again smooth to the band steel, processing is reprocessed in measures such as aligning, not only waste time and energy, and the band steel after handling still has major part can't satisfy user's service requirements, causes the lumber recovery of ultraphotic panel to be paced up and down 85% always, and 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, influenced output again, 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 at above-mentioned defective, 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 that the present invention taked 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, surplus is Fe and impurity;

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

The traveling speed of band steel in continuous annealing furnace is between 220～240m/min, and annealing temperature is controlled at above 50～80 ℃ of recrystallization temperature;

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, surplus is Fe and impurity;

The traveling speed of band steel in continuous annealing furnace should not be too high, but can not be low excessively.Traveling speed is too high, the tension force instability, and the stability of production also decreases, and degree-of-difficulty factor is corresponding to be increased; Traveling speed is low excessively, and then annealing time prolongs, can cause being with hardness of steel to descend significantly, and the steel deliquescing, and be easy to generate 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 bigger than again, so annealing temperature needs suitably to reduce.The recrystallization temperature of considering common CQ steel is about 650 ℃, so the selective annealing temperature is at 710 ℃.

Adopt 84.2% big cold-rolled compression ratio, rolling back 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 inadequately, 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, surplus is Fe and impurity;

The traveling speed of band steel in continuous annealing furnace is controlled at 235m/min;

Annealing temperature is at 730 ℃;

Adopt 85% big cold-rolled compression ratio, rolling back 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, it is characterized in that described ultraphotic cold-reduced sheet material chemical component and weight percent content are:

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, surplus is Fe and impurity;

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

The traveling speed of band steel in continuous annealing furnace is between 220～240m/min, and annealing temperature is controlled at above 50～80 ℃ of recrystallization temperature;

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.