CN101987349B

CN101987349B - Casting technology of stainless steel hydroelectric runner lower ring

Info

Publication number: CN101987349B
Application number: CN 200910012829
Authority: CN
Inventors: 李忠森; 岳景丽; 闵兴海; 王庆华; 林红
Original assignee: Angang Heavy Machinery Co Ltd
Current assignee: Angang Heavy Machinery Co Ltd
Priority date: 2009-07-31
Filing date: 2009-07-31
Publication date: 2013-01-02
Anticipated expiration: 2029-07-31
Also published as: CN101987349A

Abstract

The invention relates to a casting technology of a stainless steel hydroelectric runner lower ring, comprising the following steps: tooling preparation, molten steel pouring, opening for unpacking and heat treatment. The casting technology is characterized in that a casting section is designed according to the size of workpieces by taking progressive solidification as a rule, and a pouring model is built; a bottom pouring mode is adopted for pouring at the pouring temperature of 1550-1590 DEG C and at the pouring speed of 6-30 mm/s; the process of pouring is finished for once, and then heat preservation covering agent is added; the principle for determining the casting section is as follows: the thickness of the casting section is increased by less than 25-30 mm with raising of each meter. The heat preservation covering agent is perlite slag-accretion heat preservation covering agent. The process of heat treatment is characterized by comprising of once normalization and twice tempering treatments. The casting technology of the invention has the beneficial effect that the technology effectively solves the problems of deformation, crackles, cold shut, double skins, micro shrinkage and the like in the existing casting production process.

Description

The casting technique of stainless steel water power runner lower ring

Technical field

The present invention relates to the casting technique field, relate in particular to a kind of casting technique of stainless steel water power runner lower ring.

Background technology

The casting technique of encircling under the stainless steel rotary wheel of hydroelectricity generator group at present is that the cast compensation rate that the method that adopts rising head to mend lining under rising head increases foundry goods makes it consecutive solidification, rising head is mended lining will be with method (about 200 ℃) continuously excision after for the first time positive tempering of carbon arc air gouging before the foundry goods machine adds, and then the remaining temperature of band is carried out the tempering second time.Because workpiece body is circular arc camber, mend bad easily the causing lacking of workpiece body misrun or benefit lining amount excision of lining excision amount control, make troubles for the processing of postorder, especially temperature control is bad in the process of excision, it thermal man does not increase, it is cold again because cooling is too fast, can not the regulation temperature range in disposable continuous excision, general as can not once resecting, requirement must reheat or advance could cut after kiln is processed again, and carbon arc air gouging can the defectives such as micro-crack occur at the cutting position to the foundry goods body, mending lining other positions of position and workpiece compares thick a lot, the long-time overheated defective such as microporosity that also easily produces in this position has certain pollution to environment in the carbon arc air gouging process in addition, and operator itself is also had certain injury.

Summary of the invention

The casting technique that the purpose of this invention is to provide a kind of stainless steel water power runner lower ring, this technique have been cancelled rising head and have been mended lining, solved in foundry production, exist the problems such as distortion, crackle, cold shut pipe, microporosity are arranged.

For achieving the above object, the present invention is achieved through the following technical solutions:

The casting technique of stainless steel water power runner lower ring, comprise that frock preparation, pouring molten steel, cooling are unpacked, heat treatment, it is characterized in that, design the foundry goods cross section take consecutive solidification as principle and set up the cast model according to workpiece size, pour into a mould in the mode of rising pouring, pouring temperature is controlled at 1550 ℃-1590 ℃, poring rate 6-30mm/s, once watering expires, and adds thermal-insulating covering agent, and definite principle in foundry goods cross section is: the thickness increase in one meter foundry goods cross section of every rising is no less than 25-30mm.

Described thermal-insulating covering agent is the perlite polyslag heat-insulating covering agent.

Described heat treatment process is: after through a normalizing, drawing process the gross imperfection of cast(ing) surface is processed, advanced the kiln double tempering after the processing again;

For the first time normalizing process: the programming rate with≤20 ℃/h heats foundry goods, be heated to 690 ± 20 ℃ from room temperature, insulation is 2-4 hour under this temperature, and then with the programming rate of≤30 ℃/h foundry goods is heated, be heated to 1000-1060 ℃, insulation is 10-14 hour under this temperature, and then room temperature is down in the air cooling;

Drawing process for the first time: the programming rate with≤40 ℃/h heats foundry goods, is heated to 600-660 ℃ from room temperature, and insulation is 12-16 hour under this temperature, and then room temperature is down in the air cooling;

Drawing process for the second time: the programming rate with≤40 ℃/h heats foundry goods, is heated to 600-640 ℃ from room temperature, and insulation is 14-16 hour under this temperature, and then room temperature is down in the air cooling.

Compared with prior art, the invention has the beneficial effects as follows:

1) cancel rising head and mended lining, reduced cutting output, the defectives such as the injury micro-crack that when having eliminated carbon arc air gouging the foundry goods body has been caused, and solve the problems such as the distortion that in casting process, exists, microporosity;

2) relative wall thickness of workpiece had also reduced than originally, poring rate has increased for same workpiece, the casting defects such as cold shut pipe that produce slowly because of poring rate have been reduced, wall thickness heat treated temperature retention time also shortened accordingly, reduce the production cycle of workpiece, can carry out conventional mechanical processing after the heat treatment.

Description of drawings

Fig. 1 is the foundry goods outline drawing of mending lining with rising head;

Fig. 2 is the foundry goods schematic cross-section of mending lining with rising head;

Fig. 3 is schematic cross-section of the present invention;

Fig. 4 is cross section profile dosage schematic diagram of the present invention.

The specific embodiment

Below in conjunction with accompanying drawing the specific embodiment of the present invention is described further:

The casting technique of stainless steel water power runner lower ring comprises that frock preparation, pouring molten steel, cooling are unpacked, heat treatment, and the method is on the basis of existing technique rising head to be mended the lining cancellation, looks for solidification gradient by the processing capacity of foundry goods, makes it consecutive solidification.Its process is: by designing the foundry goods cross section according to workpiece size take consecutive solidification as principle and set up the cast model, and above-mentioned model is tested and analyze by China casting CAE casting simulation software system.This technique is poured into a mould in the mode of rising pouring, pouring temperature is controlled at 1550 ℃-1590 ℃, poring rate 6-30mm/s, once water full, the stream of demanding perfection, steadily, Quick pouring, add the perlite polyslag heat-insulating covering agent, definite principle in foundry goods cross section is: the thickness increase in one meter foundry goods cross section of every rising is no less than 25-30mm.

Heat treatment process is: after through a normalizing, drawing process the gross imperfection of cast(ing) surface is processed, advanced kiln after the processing again and carry out double tempering;

For the first time normalizing process: the programming rate with 20 ℃/h heats foundry goods, is heated to 690 ℃ from room temperature, and insulation is 4 hours under this temperature, and then with the programming rate of 30 ℃/h foundry goods is heated, be heated to 1060 ℃, insulation is 10 hours under this temperature, and then room temperature is down in the air cooling;

Drawing process for the first time: the programming rate with 40 ℃/h heats foundry goods, is heated to 660 ℃ from room temperature, and insulation is 16 hours under this temperature, and then room temperature is down in the air cooling;

Drawing process for the second time: the programming rate with 40 ℃/h heats foundry goods, is heated to 640 ℃ from room temperature, and insulation is 16 hours under this temperature, and then room temperature is down in the air cooling.

This technique can as required, be selected the form of many rising heads or the form of an annular rising head.

See Fig. 1, Fig. 2, Fig. 3, the optimization of this technique is on the basis of original technique rising head to be mended the lining cancellation, determines that take consecutive solidification as principle castings sectional makes it from the foundry goods bottom gradually to the top consecutive solidification.

See Fig. 4, after molten steel is filled with mold cavity, along with temperature descends gradually, the part that foundry goods is thin is solidified first, therefore solidify first this stainless steel water power runner lower ring foundry goods bottom, in order to guarantee from bottom to top consecutive solidification of foundry goods, the molten steel horizontal plane upwards moves L, the one-sided recruitment a of casting thickness B is no less than 12.5～15mm/ rice, and the measurement of B is considered planform characteristics and the castability requirement of foundry goods perpendicular to the profile bus among the embodiment, a takes 25mm/ rice, the artificial feeding gradient that forms consecutive solidification makes the foundry goods dense internal organization, can reach foundry goods UT-2 level flaw detection requirement.

After for the first time positive tempering, can process the gross imperfection of cast(ing) surface, then advance the kiln double tempering, reduced heat treated number of times, shortened the production cycle, reduced production cost, reduced the environmental pollution in when cutting, mended lining because cancelled rising head, reduced to mend the problems such as micro-crack that lining brings to foundry goods, cold shut, pipe, microporosity because rising head is set.The problem on deformation of workpiece has also obtained corresponding improvement.Fig. 3 section ratio Fig. 2 compares according to the consecutive solidification principle in the cross section and has done correction, but in fact total molten steel amount consumption is far below prior art.

Claims

1. the casting technique of stainless steel water power runner lower ring, comprise that frock preparation, pouring molten steel, cooling are unpacked, heat treatment, it is characterized in that, design the foundry goods cross section take consecutive solidification as principle and set up the cast model according to workpiece size, pour into a mould in the mode of rising pouring, pouring temperature is controlled at 1550 ℃-1590 ℃, poring rate 6-30mm/s, once watering expires, and adds thermal-insulating covering agent, and definite principle in foundry goods cross section is: the thickness in one meter foundry goods cross section of every rising increases 25-30mm; Described heat treatment process is: after through a normalizing, drawing process the gross imperfection of cast(ing) surface is processed, advanced the kiln double tempering after the processing again;