JPS5841601A - Skin pass rolling method with less degradation in quality of material by aging - Google Patents

Abstract

PURPOSE:To decrease the degradation in the quality of materials by aging by performing skin-pass rolling with upper and lower work rolls in an asymmetrical state. CONSTITUTION:The diameters of the upper and lower work rolls of skin-pass rolling mills are varied, or the peripheral speeds of the upper and lower work rolls are varied or only one of the upper and lower work rolls is driven. If a steel material is subjected to skin-pass rolling with the upper and lower work rolls in an asymmetrical state in such a way, many movable dislocations are introduced into the steel plate, whereby the degradation in the quality of materials is decreased. Either of lubrication with soluble oil, etc. or nonlubrication may be employed as lubricating conditions in skin-pass rolling.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a special temper rolling method that causes less material deterioration due to aging.

In general, annealed I''!l+ steel sheets have an elongation at the yield point, and if they are subjected to press working as is, they will develop surface defects called stretcher strains and buckles, and the product will lose its commercial value. It is well known that 1 to 2X temper rolling is performed to eliminate point elongation.

General cold-rolled steel sheets are solid solution (0)% except for special cases.
It is also well known that after skin pass rolling, there is strain aging that changes the properties of the steel sheet over time.Changes in material properties due to strain aging include recovery of yield point elongation and increase of yield point. , decrease in elongation, etc. It is also known that the recovery of elongation at yield point generally decreases as the temper reduction rate increases, and that the decrease in elongation decreases as the temper reduction rate decreases. Therefore, the key to reducing workability deterioration due to aging is to eliminate the yield point elongation under shearing pressure and to suppress recovery of the yield point elongation due to aging.

As a 61/J pressure method for eliminating yield point elongation under light pressure, pressure adjustment using small diameter rolls with rolls whose pressure and surface ITi degree are compatible has been known. As is well known, the role of temper rolling is to adjust the surface roughness of the plate, (
2) Securing a flat space between the steel plates, and (3) eliminating the yield point elongation of the steel plate to prevent stretchers and trains during processing. Therefore, in the known method of the above i, Fi, (1)%
The role of (2) cannot be fully satisfied.

The present inventors have conducted various studies on the NlAl rolling method of the above-mentioned skin pass rolling (without any loss in performance, slow recovery of elongation at yield point due to aging, and less deterioration of workability due to aging, and have developed the present invention. completed.

The gist of the present invention is to reduce the deterioration of workability and elongation at yield point due to aging, which is characterized by performing temper rolling with the upper and lower work rolls being substantially asymmetrical; It is a temper rolling method that causes less material deterioration.

The present invention will be explained in detail below.

The temper rolling of the present invention in which the upper and lower work rolls (hereinafter also referred to as rolls) are asymmetrical means that the roll diameters of the upper and lower rolls are actually different as shown in Figure @1, or the upper and lower rolls are Either the circumferential speed of the rolls is different in actual percentage, or only one of the upper and lower rolls has J'! <! 1ilJ
It means to do something, etc.

In addition, in Fig. 41, S is a steel plate, ■ is li (besuke roll, R
' is the non-driving roll, DI+D2 is the roll diameter, V+ +
V2 i”J: Indicates roll circumference.

Although it is not clear why the AJJJ rolling method of the present invention provides superior material properties after aging, it can be assumed that a larger number of mobile dislocations are introduced into the steel sheet than in the conventional method.

The effects of the present invention can be obtained under any of the lubrication conditions during skin pass rolling, such as lubrication using soripul oil or the like, or 1tij lubrication. The present invention is effective even when the roll surface condition is bright or dull.

The sintered material used for temper rolling of the present invention is sintered ε, ':J
The characteristics of the present invention are not lost by the method 5. Either box-annealed material or continuously annealed material may be used.

The effects of the present invention are not limited to annealed cold-rolled steel sheets and high-strength cold-rolled steel sheets, but are also applicable to thin hot-rolled steel sheets and surface-treated steel sheets, and have great effects.

A practical example will be described below.

Example 1 Table 1 shows the results of skin pass rolling performed at the same roll circumferential speed using pressure regulators with different diameters of upper and lower work rolls, and the material properties after aging were investigated.

The temper-rolled material is J'IS 5P, which is made into a continuous ring.
It is of OI) class. Oil-based Soliple oil was used for lubrication during temper rolling. The temper rolling reduction is the temper rolling reduction +029 g at which the elongation at yield point in the 1il JI rolling disappears. Accelerated aging was performed at 100°C x 60'.

In Table 1, the recovery of yield point elongation after aging is almost the same as that of the conventional method, but the elongation is higher. However, if the diameter of either roll becomes too small, the roll surface roughness will change with a small amount of temper rolling, which increases the number of roll changes, which is not desirable from an industrial perspective. It is preferable to set the diameter to be equal to or larger than ''/2 of the roll diameter.

Example 2 Table 2 shows the results of investigating the relationship between skin pass rolling conditions and material properties after aging when the circumferential speeds of the upper and lower work rolls were changed.

The materials and other conditions are the same as for the table in Table 1.

Table 2 Table 2 shows that when temper rolling is performed by changing the circumferential speed f of the upper and lower work rolls, the elongation at the yield point after aging is smaller than that of the conventional method, or even though it is the same, the elongation is large and the yield point is low. It is soft. However, as the circumferential speed ratio of the upper and lower work rolls increases, as can be easily inferred from rolling theory, slip occurs between the surface of the ferrule and the surface of the roll, resulting in surface roughness, which is one of the functions of temper rolling. Therefore, in the present invention, the circumferential speed ratio of the upper and lower work rolls is mainly adjusted within the range of the reduction rate K for tempering pressure polygon (1.15 + 1.0).
-7-■- It is preferable to apply it once.

Example 3 Table 3 shows the results of investigating the relationship between skin pass rolling by driving either the upper or lower single roll and the material properties after aging. The raw material and other skin pass rolling conditions are the same as in the first roll.

Table 3 You can expect to improve your sexual performance.

The asymmetrical upper and lower roll temper rolling method used in the present invention has conventionally been used as a cold rolling mill for t-j, jff: a small bundle of knowledge, but by applying this to the temper rolling method, Since deterioration of properties is prevented, it is novel and extremely useful industrially.

In other words, users of steel sheets can improve their press failure rate. Additionally, steel machine manufacturers can ensure excellent press workability at low cost. That is, there is a multi-S nit, which saves energy by lowering the annealing temperature, improves productivity, and avoids cost increases due to special adjustment of steel components, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the basic principle of an embodiment of temper rolling of the present invention. , -21--+8 is a steel plate, ■ is a driving workpiece IJ-le, 1'
is the non-driven work roll, DI+D2 is the work roll f
” s V+ HV 2 digits 0 - Indicates crawl circumferential speed. Agent Patent attorney Masamitsu Akisawa and 2 others ra> (6)
<cノ')F'
Figure 1

Claims (1)

[Claims] (1) A temper rolling method that reduces material deterioration due to aging, which is characterized by temper rolling with an asymmetrical state of upper and lower work rolls.