CN1042805C

CN1042805C - Anti-oxidation method for inwall of steel pipe inlaid in casting

Info

Publication number: CN1042805C
Application number: CN94110161A
Authority: CN
Inventors: 张新一; 王德生
Original assignee: Benxi Iron & Steel Co
Current assignee: Benxi Iron & Steel Co
Priority date: 1994-03-28
Filing date: 1994-03-28
Publication date: 1999-04-07
Anticipated expiration: 2014-03-28
Also published as: CN1107399A

Abstract

The present invention discloses an oxidation preventing method for the inner wall of a steel pipe laid in a casting. In order to prevent the inner wall of a steel pipe laid in a casting from generating an iron oxide coating when the inner wall is baked at high temperature, nitrogen gas is led into the laid steel pipe in the processes of pouring the casting and cooling the casting; after the nitrogen gas is stopped from leading into the steel pipe, a pipe head of one end of the laid steel pipe is instantly sealed by a special protective cover to prevent air from entering into the steel pipe, and the non-oxidizing atmosphere can be maintained in the steel pipe; thus, the present invention can achieve the purposes that the iron oxide coating can not be generated on the inner wall of the steel pipe laid in the casting, and the inner wall of the steel pipe which needs to be treated by pickling can be omitted; thus, positive economic effects can be generated.

Description

A kind of steel pipe embedding method

The present invention relates to a kind of steel pipe embedding method.

When casting, need to be bumped into the steel pipe of cooling usefulness sometimes as required in foundry goods inside.When casting this class foundry goods, elder generation curves certain shape with the seamless steel pipe of certain diameter before cast, is placed in the casting mold and fixes, and pours into a mould then.The baking that is subjected to high-temperature liquid metal owing to the steel pipe that is bumped into foundry goods is scalded, air effect in the steel pipe in addition, cause the steel pipe inwall to produce very thick one deck iron scale, influence cooling water in the steel pipe to the cooling effect of foundry goods itself, and after long-term the use, the iron scale blocking pipe that comes off in the pipe, the service life of reducing foundry goods.Therefore, both at home and abroad about design and manufacturing sector, for example Kawasaki, Japan iron Co., Ltd. and Beijing Iron﹠Steel Design﹠Research Institute etc. clearly stipulate in technical conditions, must carry out pickling processes to the inwall of the steel pipe of inlaying in the foundry goods, to remove the iron oxide cortex.

At present, the method for the steel pipe inner wall oxide iron iron sheet layer of inlaying generally adopts the pickling processes method in the cleaning foundry goods.Because iron oxide cortex compact structure, thereby pickling is difficult to clean out, and also there is fragile foundry goods itself in pickling simultaneously, and troublesome poeration is wasted man-hour, problems such as consumption fund.

Inner wall oxide when the objective of the invention is to prevent the steel pipe castingin forms a kind of nonoxidizing atmosphere in steel pipe, make the steel pipe inwall not produce the iron oxide cortex, and then exempts acid cleaning process.

The object of the present invention is achieved like this: in pouring cast part and foundry goods cooling procedure, inlay feeding inert gas one nitrogen in the steel pipe to foundry goods, drive away the air in the steel pipe; After stopping logical nitrogen, with the end sealing of a privacy protection seal cover, avoid air to enter in the steel pipe at once with the edge steel pipe; Treat to take off when foundry goods is cooled to uniform temperature the privacy protection seal cover.

Use the steel pipe of this method castingin in the foundry goods, for example blast furnace cooling stave etc. can be removed from pickling cleaning edge inside pipe wall iron oxide cortex process, saves time, laborsaving, province's fund, not deterioration foundry goods.

Concrete grammar of the present invention is as follows:

The seamless steel pipe that earlier preparation is bumped into foundry goods is put in the casting mold on request and fixes, and the tube head at its two ends all is exposed at outside the sandbox, and tube head one end is connected with nitrogen pipeline, connects part and tightens used nitrogen pressure 〉=0.4MPa with joint.When beginning to cast, open the nitrogen pipeline valve, in the steel pipe that is bumped into, lead to nitrogen while pouring into a mould.The nitrogen that feeds can reclaim or emptying by the other end of tube head outside being exposed at sandbox.Pour and treat to stop after casting temperature is reduced to below 1150 ℃ logical nitrogen; at once pull out the sebific duct that connects tube head then; with of the other end sealing of privacy protection seal cover with steel pipe; in case enter air in the pipe; treat after casting temperature is reduced to below 500 ℃ the privacy protection seal cover to be taken off, so far finish the anti-oxidation technology of steel pipe inwall of inlaying in the foundry goods.

Claims

1. steel pipe embedding method; it is characterized in that in pouring cast part and foundry goods cooling procedure, in the edge steel pipe, feeding nitrogen; after stopping to feed nitrogen in the edge steel pipe, the end with the edge steel pipe seals with the protection seal cover at once, takes off the protection seal cover when casting temperature is lower than 500 ℃.

2. a kind of steel pipe embedding method according to claim 1 is characterized in that an end of the steel pipe of inlaying should be when casting temperature is lower than 1150 ℃ with the sealing of protection seal cover.