JPH0829330B2 - Long and small diameter compound roll - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an elongated rolling composite roll that is used for controlling the shape of a rolled steel sheet.

(Prior Art) In recent years, a hot rolling mill has adopted a new rolling method for controlling the shape of rolled steel sheet. For example, there are a method of moving the work roll in the axial direction and a method of forcibly bending the work roll.

Conventionally, composite rolls applied to these new methods have a barrel length l _B and a barrel diameter D _B , and l _B / D _B is about 2.0 to 3.5, and D
_B was Φ500 mm or more.

Therefore, in terms of strength, the material of the neck portion could sufficiently withstand a cast iron-based material such as ductile cast iron or an adamite material. On the other hand, as the outer layer, which is the rolling-use layer that is in direct contact with the rolled material, a known roll material such as an adamite material, a high chromium material, a high alloy grain material, or an alloy chilled material is appropriately adopted depending on the rolling conditions. The outer layer and the body core are usually welded and integrated by centrifugal casting.

(Problems to be Solved by the Invention) By the way, in a long small-diameter composite roll having l _B / D _B of 4 or more and D _B of less than Φ500 mm, the diameter of the core portion and the neck portion also becomes smaller along with the diameter of the cylinder. However, the conventional composite roll has a problem that the fatigue strength of this portion is insufficient. Further, since the cylinder diameter is small, the rotation speed is higher than in the conventional case, the wear resistance is insufficient, and the roll life is short.

The present invention has been made in view of the above problems, the outer peripheral surface of the body core portion, the outer layer as a rolling use layer is formed to form the body portion, the neck portion is integrally extended to both ends of the body core portion. Another object of the present invention is to provide a composite roll having an outer layer having excellent wear resistance and a core portion and a neck portion having high fatigue strength, which are long and small in diameter.

(Means for Solving the Problems) In the composite roll of the present invention made to achieve the above object, the outer layer 2 as a rolling use layer is formed on the outer peripheral surface of the body core portion 1 to form the body portion 3, in composite roll neck portions 4 are extended integrally to both ends of the Duasyn portion 1, the ratio l _B / D _B is 4 or more and D _B of the body length l _B and barrel diameter D _B Fai500mm
The outer layer 2 is formed of a high alloy material having excellent wear resistance, and the outer layer 2 and the body core portion 1 are diffusion-bonded by hot isostatic pressing to form the body core portion 1 and the neck portion 4 , 4 are formed of a tough steel, and the neck portions 4, 4 are welded and joined in the vicinity of the body end, which constitutes the invention.

(Example) The long small-diameter composite roll according to the example shown in FIG.
An outer layer 2 formed of a high alloy material having excellent wear resistance is diffusion bonded to the outer peripheral surface of a body core portion 1 formed of a tough steel by hot isostatic pressing (hereinafter referred to as HIP) to form a body portion. 3, and neck portions 4 extending from both ends of the body core portion 1 are welded to each other near the ends of the body portion.

The body core portion 1 and the neck portion 4 are formed of a tough steel material such as carbon steel for machine structure or alloy steel for machine structure such as SCM material and SNCM material. On the other hand, a high alloy powder sintered body can be exemplified as the high alloy material forming the outer layer 2.
As the high alloy powder, it is possible to use tool steel powder such as SKH material and SKD material, powder obtained by adding ceramic powder such as WC and SiC to these powders, and powder having appropriate wear resistance. These powders are sintered by HIP and are diffusion-bonded to the body core 1. Further, as another high alloy material, a tool steel material may be melted, forged, and processed into a cylindrical shape. In this case, a high-alloy cylindrical material is fitted on the shaft member 7 which will be the body core 1, and both are diffusion-bonded by HIP.

In order to manufacture the roll, the length of the body core 1 and the lengths of the neck portions 4 and 4 at both ends of the body core 1 from the body ends to the welded joints 5 and 5 (as long as the welding allowance can be secured) , Usually 200 mm on one side is sufficient.) After preparing a shaft member 7 for a body core having the outer layer 2 on the shaft member 7 by diffusion bonding by HIP, a predetermined length is provided on both ends of the shaft member 7. The shaft member 8 for a neck which forms the neck remainder is welded so that the neck portion 4 of the can is obtained. As described above, in manufacturing the roll of the present invention, it is sufficient for the HIP device to have a processing chamber capable of accommodating the shaft member 7 for the body core, which is slightly longer than the body length, and it is possible to reduce equipment costs and operating costs. Can be planned.

The long small-diameter composite roll of the present invention has a ratio of the body length l _B to the body diameter D _B.
l _B / D _B is 4 or more and D _B is less than Φ500mm. Conventionally, many rolls for hot strip mills have an initial diameter of Φ600 mm or more and a waste diameter of less than Φ500 mm due to the relationship between rolling speed and roll wear. The reason is that the hot strip mill cannot transmit the drive torque unless the diameter of the neck portion and the wobbler portion (drive connecting portion at the tip of the neck portion) are more than a certain amount due to the rolling load. This is because the diameter, and hence the body diameter, had been determined.

Next, a specific manufacturing example of a long and small-diameter composite roll (l _B : 1450 mm, D _B : Φ330 mm, l _B / D _B : 44, total length 3600 mm) for a hot strip mill will be described.

(1) Φ300 × length, which is the core 1 and both necks 4,4
Prepare 3800 mm SCM shaft material, and use this for the core member shaft member (1800 mm) 7 that forms part of the core part 1 and neck part, and the neck shaft member (1000 mm x 2 that forms the rest of the neck part).
Cut into 8) and 8).

(2) The shaft member 7 for the body core is concentrically arranged inside the steel pipe having an inner diameter of Φ340 × length 1500 mm with the center positions in the longitudinal direction aligned, and a gap is formed between the inner surface of the steel pipe and the outer surface of the shaft member 7 at one end of the steel pipe. After closing the opening, the SKH-57 powder having the following composition was filled in the gap. At this time, filling was performed while applying vibration so that dense packing was performed. After the filling was completed, the other end of the steel pipe was sealed, and the inside was evacuated and evacuated.

・ SKH-57 composition (% by weight) C: 1.38%, Si: 0.39%, _MN : 0.28% Cr: 4.32%, MO: 3.68%, W: 10.25% V: 3.54%, Co: 9.69%, balance balance By Fe (3), this sealed tube is housed in a HIP device at 1150 ℃, 200kg
/ cm ² treated and diffusion bonding a sintered body or outer layer 2 to the Duasyn shaft member for 7 with sintering SKH material powder. After that, the steel pipe was removed, and the shaft members 8 for neck were butt-welded to both ends of the shaft member 7 for body core.

(4) The obtained composite roll material was roughly processed and then subjected to quenching and tempering heat treatment. As a result, the distortion of the welded joint was completely removed.

(5) By the finishing process, the expected long and small diameter composite roll was obtained. The outer layer surface hardness of the product is HS83, and the neck part 4
It was the HS37.

(Effects of the Invention) As described above, the long small-diameter composite roll of the present invention is
The outer layer is made of high-alloy material with excellent wear resistance, and the body core and neck are made of tough steel, so even if the body is made to have a long, small diameter, sufficient fatigue strength and wear resistance It was possible to provide the above, and it was possible not only to prolong the service life but also to downsize the hot strip mill. Further, since the outer layer and the body core are diffusion-bonded, there is almost no risk of mixing the high alloy component of the outer layer into the body core, and the toughness of the body core is not impaired. Further, since the neck portion is welded near the end of the body portion, the outer layer may be diffusion-bonded to the shaft member which is slightly longer than the body length in the diffusion joining between the body core portion and the outer layer. Therefore, it is not necessary to HIP the entire roll,
A large HIP device is not required, and equipment costs and operating costs can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a long and small diameter composite roll according to an embodiment. 1 ... Body core, 2 ... Outer layer, 3 ... Body, 4 ... Neck, 5 ... Welding joint.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Cho Morikawa 64 Nishimukojima-cho, Amagasaki City, Hyogo Prefecture Kubota Iron Works Co., Ltd. Amagasaki Plant (72) Inventor Nobuaki Maeke Nishimukojima-cho, Amagasaki City, Hyogo Prefecture Kubota Iron Works Amagasaki Co., Ltd. In the factory (56) Reference JP 61-1404 (JP, A) JP 61-219406 (JP, A) JP 59-225806 (JP, A) JP 60-36355 (JP, B2) ) JP 60-59076 (JP, B2)

Claims (1)

[Claims] 1. An outer layer 2 which is a layer used for rolling is formed on an outer peripheral surface of a body core portion 1 to form a body portion 3, and a neck portion is provided at both ends of the body core portion 1.
4,4 In composite roll which extends integrally, be less than body length l _B and barrel diameter D ratio l _B / D _B is 4 or more and D _B and _B Fai500mm, the outer layer 2 wear The outer layer 2 and the body 1 are diffusion-bonded by hot isostatic pressing, and the body 1 and the necks 4, 4 are made of a tough steel material. A long, small-diameter composite roll characterized in that the neck portions 4, 4 are welded and joined together near the body end.