JPS6234688A - Welding structure of stock for stainless steel clad sheet - Google Patents

Abstract

PURPOSE:To prevent the generation of the hot working crack in a rolled weld zone by subjecting the four peripheral end parts of the clad sheet composed of steel and stainless steel to a hot rolling after welding it by using the material specifying the contents of carbon and titanium. CONSTITUTION:The mating face of the steel stock of a base metal 1 and the stainless steel of a cladding stock 2 is cleaned and welded. A weld zone 3 is formed by fixing the four peripheral end face 2a of the cladding sheet 2 to the base metal 1 with welding. This weld zone 3 is formed by the welding material containing less then 0.90% titanium with the dead soft steel containing less than 0.05wt% carbon. No hot working crack is caused on the weld zone subjected to a hot rolling by the welding structure of said open method stock. No work roll is broken as well in case of the weld zone being rolled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a welding structure between a composite material and a base material of a hot-rolled open type stainless clad steel sheet material.

(Prior Art) The conventional technology will be explained with reference to FIGS. 1(a) and 1(b).

As shown in Fig. 1 (a), as a material for a stainless clad steel sheet (hereinafter simply referred to as clad material) before rolling into a stainless clad steel sheet, a stainless steel composite material 2 is coated on one side of a base material 1 which is a steel material. Clean both mating surfaces and bring them into close contact, and weld the four peripheral end surfaces 2 m and 2 m of the composite material 2 to the base metal l# to make an open type single-sided clad material A, and as shown in Figure 1 (b). A stainless steel composite material 2 is placed on both sides of a steel base material 1, each mating surface is cleaned and brought into close contact, and the four peripheral end surfaces 2m and 2m of the composite material 2 are welded to the base material 1 to create an open type double-sided clad material. B is Toshishita.

Conventionally, the four peripheral end surfaces 2a of the composite material 2.

Y2O2 or Y310, which has the welding steel composition shown in Table 1, was used as a welding material for welding 2a to base metal 1''.

(The following is a blank space) Table 1 (H) (Problems to be solved by the invention) As shown in Fig. 5, for example, a single-sided clad material A1ft
:/When rolling in the direction of arrow C using a rolling mill consisting of a matsuku roll BUR and a work roll WR, hot working cracks 4 occur in the rolled welded part 3, and the welded part 3 cracks as shown in FIG. A flaw or abnormal wear 5 had occurred on the surface of the work roll WR to be rolled. These situations are the same in rolling the two-sided double-sided material B.

This situation occurs with welding rod Y 3.09.

This is due to the fact that the weld metal of Y310 in the welded part 3 is hard and lacks elongation, which in turn results in poor hot workability. Second
Taking Y2O2 as an example, which is shown by one curve in Figures 4 to 4, 95
At temperatures below 0°C, both elongation and area of area decrease, which corresponds to a sharp increase in tensile strength. It should be noted that almost the same tendency is observed for Y310 as well. And clad steel material A
Please note that hot rolling of B is from 1250℃ to 850℃~90℃.
This is done at temperatures down to 0°C. Also, welding rod Y309゜Y3
'IO is relatively expensive.

(Means for Solving the Problems) The present invention has the following configuration in order to solve the above problems in rolling a material for a stainless clad steel plate. That is, the present invention is an open method in which the contact surfaces of a steel base material and a stainless steel composite material are cleaned and brought into close contact with each other, and the four peripheral end surfaces of the composite material are welded to the base material and then hot rolled. Welding of a stainless clad steel plate material in which the welding part of the stainless clad steel plate material is welded to extremely mild steel with a carbon content of 0.05% by weight or less using a welding material containing 0.90% by weight or less of titanium. It is a structure.

(Function) The material for a stainless clad steel plate according to the present invention is obtained by welding the four circumferential end surfaces of a stainless steel composite material to a steel base material, so the composite material and base material are rolled as one body, and The welding part is made of extremely mild steel with a carbon content of 0.05 - 0.9% by weight or less.
Since it is welded with a welding material containing less than 0 weight of titanium, the hardness of the welded part is low, the elongation is good, and it is easily rolled into a stainless clad steel plate.

(Example) An example of the welded structure of the material for stainless clad steel plate according to the present invention will be explained based on FIGS. 1(a) and (b).
゜ 1 is a base material of steel, 2 is a composite material of stainless steel, and the mating surfaces are cleaned and brought into close contact.
m and 2 m are welded and fixed to the base metal 1 to form the welded part 3. Figure 1 (a) shows the open type single-sided clad material A.
FIG. 1(B) shows an open type double-sided cladding material B, respectively.

This welded portion 3 is made by welding extremely mild steel with a carbon content of 0.05% by weight or less using a welding material containing titanium of 0.90% by weight or less. The reason why titanium is added here is to fix carbon. In addition, the content of titanium is 0.90
The reason for setting the weight as - is that even if the content exceeds this value, the hot workability of the welded part will not improve.

Figure 2 shows temperature (°C) on the horizontal axis and elongation (%) on the vertical axis.
Figure 3 is a diagram showing the material (rod or wire) with a curve .
Figure 4 is a diagram showing the welding material according to the present invention as a curve 11, where the horizontal axis is the temperature (C) and the vertical axis is the tensile strength Kff/fi''), and the Y2O2 material is shown as a curve 11. 11 is a diagram showing a welding material according to the present invention with a curve (■).

As can be seen from each diagram, the welding material according to the present invention containing 0.90% by weight or less of titanium in extremely mild steel with a carbon content of 0.05% by weight or less has a carbon content of 950% by weight or less compared to Y2O2.
It has excellent elongation and drawing properties even at temperatures below 0.degree. C., and its tensile strength tends to be significantly inferior, so it has particularly excellent hot workability at relatively low temperatures.

Next, an example of application will be explained.

Using 5S41 as the base material 1 and SUS 304 L as the composite material 2, welding of the welding part 3 was carried out using the welding material with the composition shown in Table 2 under the welding conditions shown in Table 3, and a welding material with a thickness of 130H was obtained. An open-type single-sided cladding material A was manufactured.

Table 2 Table 3 The single-sided cladding material A was then hot rolled into a stainless steel plate with a thickness of 3 mm.

As a result, the hardness of the welded part 3 after being rolled is Hv(1
0Kff) was 150, which was sufficiently low by t, and no hot working cracks occurred due to rolling of the welded part 3.

Furthermore, the welding material according to the present invention can also be applied to the following cases. In other words, the double-sided cladding material B is 3m+~611m
11, the double-sided clad steel plate thus obtained was made into a coiled block, and both ends of the cough block were welded,
In some cases, the sheet is cold rolled into a thin sheet of 2 am to 0.4 fi as a series. At that time, conventionally, both ends of the block were Y2
Welding was performed using O2 or Y310, but the welded part was hard and had poor elongation, causing wear and surface defects on the work roll, and the welded part sometimes broke. The above-mentioned problems can be solved by applying the present invention to welding of such a coil build azo.

(Effects of the Invention) As can be understood from the above explanation, according to the open type welding structure of the material for stainless clad steel sheet according to the present invention, during rolling of the stainless clad steel sheet, the rolled weld part is heated. The life of the work roll can be extended without causing processing cracks or damaging the work roll when the welded part is rolled, and the cost of welding materials can be reduced.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a diagram of an embodiment of the welded structure of a stainless clad steel sheet material according to the present invention, and FIG.
Figure 3 is a temperature-elongation relationship diagram of welding material, Figure 3 is a temperature-restriction relationship diagram of welding material, Figure 4 is a temperature-tensile strength relationship diagram of welding material, and Figure 5 is a relationship diagram of welding material temperature-tensile strength. The figure shows the occurrence of hot working cracks during rolling of a material for a stainless clad steel plate using the conventional open method, and FIG. 6 similarly shows the occurrence of damage on the work roll surface. 1: Base material, 2: Mixed material, 2a: Side end surface in rolling direction, 3: Welded part, 4: Hot work crack, 5: (of work roll surface)
Defect or Abnormal Wear Agent Patent Attorney (Mae) 1) Interest Figure 1 Figure 5 Figure 6 Figure 2 Temperature (0C) Figure 3 Temperature (0C) Figure 4 Temperature (0C)

Claims (1)

[Claims] A material for open type stainless clad steel sheets in which the contact surfaces of the steel base material and the stainless steel composite are cleaned and brought into close contact with each other, and the four peripheral edges of the composite are welded to the base material and then hot rolled. A welded structure of a material for a stainless clad steel plate, characterized in that the welded part is welded to extremely mild steel with a carbon content of 0.05% by weight or less using a welding material containing 0.90% by weight or less of titanium. .