CN1121446A

CN1121446A - Roller renovation technology capable of improving welding layer property

Info

Publication number: CN1121446A
Application number: CN 95110227
Authority: CN
Inventors: 鲁宝波; 刘明旭; 唐子威
Original assignee: Continuous Rolling Plant Of Benxi Iron & Steel Corp
Current assignee: Continuous Rolling Plant Of Benxi Iron & Steel Corp
Priority date: 1995-05-12
Filing date: 1995-05-12
Publication date: 1996-05-01

Abstract

The present invention discloses a kind of built-up welding technology for repairing roller, which adds the procedure of differential temp. spray quenching heat treatment in the well known roller repairing technology. By using said method, the welding layer of the repaired roller becomes grain refinement and the welding stress and hardening can be eliminated ideally, thus the hardness of the roller body is uniform and the mechanical property is improved, the service life is increased and the productive cost. is lowered.

Description

A kind of roll renovation technique that can improve the layer function

The present invention relates to a kind of renovation technique of roll, particularly relate to and a kind ofly can reduce roll overlay cladding welding stress and hardenability in the built-up welding repair process, and make the uniform roll renovation technique of hardness of roll body.

In steel rolling is produced, because roll is the main machining tool that directly contacts, forces rolled piece generation plastic deformation with rolled piece, it promptly to bear very big dynamic pressure and with bigger sliding speed of intermetallic and bigger bending stress, bear the bigger temperatures involved of amplitude of variation again and also constantly be worn, thereby its consumption is very big.In order to improve effectively the service life be repaired roll, reduce the steel rolling production cost, the professional is improving the roll renovation technique, is improving and carried out many useful discussions and experimental study aspect the roll service behaviour after repairing.In the technology of the built-up welding repaired roller of Japan 162-758D patent and Soviet Union SU1371727 patent disclosure, the roll barrel hardness that is repaired requires and the mechanical performance of overlay cladding all is by selecting different welding wires, solder flux and corresponding welding procedure satisfy, this is just to the welding wire material, the prescription of solder flux has proposed specific (special) requirements, the in enormous quantities reparation of roll is restricted, make referrals in the Related domestic documents (as the 43rd page of " welded tube cold roll automatic submerged-arc bead welding renovation technique " literary composition of " welded tube " 91 years the 3rd volume) and when the built-up welding repaired roller, should select low-alloy welding wire and alloy total amount, also should select optimum Preheating Temperature to aim at weldering position preheating and best built-up welding standard for preventing that crackle from producing greater than 20% alloy flux or high basicity bonded flux.Even the process of taking to satisfy above-mentioned many requirements is implemented the reparation of breaker roll, its built-up welding stress of the roll that is repaired is eliminated still desirable down with sclerosis, and, surfacing part layer crystal grain is thick, when local annular stack is welded, the hardness of roll body inequality, rolling middle roll two ends easily produce tapering, and no matter whole built-up welding still is local built-up welding, and layer all easily peels off in the use.In a word, it is relatively poor that the deficiency of existing built up welding technique of restoring roller causes roll to repair the back mechanical performance, seriously limited roll service life, thereby strengthened the production cost of rolled products.

Task of the present invention is to seek a kind ofly can improve the mechanical performance be repaired roll, improve the roll renovation technique in its service life.

Task of the present invention is finished by following technical proposals.Main technique content and program that this technical scheme comprises are:

(1) earlier the roll that will repair is carried out conventional mechanical process before the built-up welding;

(2) again the roll after the mechanical process is carried out conventional preheating;

(3) roll that reaches the preheat temperature value is carried out conventional built-up welding;

(4) roll after the built-up welding is carried out conventional annealing;

(5) this roll being implemented conventional postwelding fine finishining processing makes it reach desired dimensional accuracy.

It is characterized in that this roll renovation technique also is included in " conventional roughing before this roll of built-up welding reparation implemented spray and quench → this roll is implemented differential temperature spray heat treatment of the quenching " two procedures that is increased between above-mentioned known technology content and program (4) and (5).

The present invention compares with known built up welding technique of restoring roller, spray the heat treatment of quenching owing to increased differential temperature, the welding stress and the sclerosis that produce when making the roll of built-up welding reparation at high temperature eliminate built-up welding ideally, and its crystal grain of energy refinement, this just can make the roll that adopts this renovation technique to repair more even than the roll hardness that adopts existing renovation technique to repair, wearability is better, thereby improved the mechanical performance that is repaired roll, is improved the service life of roll, thereby reduces the rolled products production cost.

The present inventor provides following preferred forms:

1, at first conventional machined is carried out at the roll position that will repair, made this roller substrate surface obtain cleaning.

2, the roll after the machined is put into the built-up welding stove,, make roller temperature reach 400 ℃-500 ℃, this roll is carried out preheating with the firing rate of 15 ℃ of-20 ℃/H that per hour heat up.

3, under the condition that keeps 400 ℃ of-500 ℃ of temperature, welding machine voltage is transferred to 36V-38V, the solder flux that is modulated into the wire feed rate of the built-up welding speed of the welding current of 550A-650A, 350-400mm/min and 0.5-1.8M/min, with 25Cr3Mn2MO2 welding wire and homemade SJ3OI and two kinds of flux compositions of SJ102 is implemented the automatic submerged-arc built-up welding to the roll of the roughing mill working roll of 1700mm hot steel strip continuous rolling unit and backing roll thereof and so on.

4, to the firing rate of the intact roll of above-mentioned built-up welding, be heated to 500 ℃-600 ℃, be incubated after 30-50 hours with 20 ℃ of-30 ℃/H, again with the cooling rate of 20 ℃ of-30 ℃/H make its reduce to≤150 ℃ naturally cool to normal temperature with stove then.

5, this roll that is cooled to normal temperature is carried out roughing, make it satisfy spray and quench after the requirement, in the conventional differential temperature stove of it can being packed into it is implemented the spray heat treatment of quenching, the concrete spray operation of quenching can be carried out as follows:

(1) earlier make this roll be warming up to 150 ℃-250 ℃ and be incubated 5 hours with the firing rate of 15 ℃ of-30 ℃/H, make roller temperature rise to 450 ℃-500 ℃ with the firing rate of≤40 ℃/H again, be incubated 6-9 hours, then, firing rate with 90 ℃ of-150 ℃/H makes the roller temperature rise to 850 ℃-950 ℃ insulations 4-7 hours fast, makes the temperature difference of this roll roll surface and roller core reach 200 ℃-450 ℃.

(2) can open the differential temperature stove after insulation reaches the stipulated time, immediately this roll is sprayed the heat treatment of quenching fast, in 4-7.5 hours, make the roll surface temperature of this roller reduce to 250 ℃-300 ℃, then, banking again, make roller temperature rise to 400 ℃-600 ℃ with the firing rate of≤30 ℃/H, be incubated after 40 to 70 hours, just can allow this roll reduce to normal temperature naturally when making the roller temperature drop to≤150 ℃ with stove with the cooling rate of≤25 ℃/H.

6, finish and again this roll is carried out conventional fine finishining after the spray of above-mentioned differential temperature is quenched, make it reach desired dimensional accuracy.

According to experimental results show that of above-mentioned preferred forms repaired roller, compare with employing prior art renovation technique, the roll that adopts the present invention to repair, its hardness of roll body is more even, wearability better and roll can be enhanced about more than once service life at least, has reduced the production cost of rolled products significantly.

Claims

1, a kind of built up welding technique of restoring roller, it is characterized in that: after the roll that will repair being welded successively preceding machined, conventional preheating, conventional built-up welding, post-weld annealed processing according to known built up welding technique of restoring roller requirement, with this is being repaired in the middle of the operating procedure of roll before carrying out conventional fine finishining conventional roughing before having increased the spray that this roll is carried out successively and quenching, the differential temperature spray Technology for Heating Processing program of quenching.