CN1693526A - Hard hollow alloy ball iron mould material for vehicle mould and its making method - Google Patents

Abstract

An air-hardened alloyed nodular cast iron for the die of car contains C (3.5-3.8 wt.%), Si (2.1-2.5), Mn (0.5-0.8), Cr (0.1-0.3), Cu (0.8-1.0), Mo (0.4-0.6), Ni (0.2-0.4), P (0-0.02), S (0-0.02) and Fe (rest). Its preparing process includes such steps as proportionally mixing raw materials, smelting, casting, quenching in audio induction mode, heating to 850-950 deg.C, and quenching in air. Its advantages are high hardness and high mechanical performance.

Description

Vehicle mould hard hollow alloy ball iron mould material and preparation method thereof

Technical field

The present invention relates to a kind of vehicle mould with hard hollow alloy ball iron mould material and manufacture method thereof, belong to the alloy cast iron material manufacturing process technology field.

Background technology

Moulds such as automobile panel die, punch and blank holder belong to Drawing Die, in the course of the work, bear intensive friction, radial stress and stress under compression, often because size wearing and tearing and surface produce groove and scrap, so cladding member mold should have higher hardness and wear resistance.Because its size is bigger and complex-shaped, adopt the cast alloy iron casting to form usually, wherein Cr-Mo cast iron is because of having good comprehensive performances, and is used widely.But water the cladding member mold that casts out after carrying out surface treatment by this class cast alloy iron,, phenomenons such as the not enough or size deviation of the Abdeckteil surface accuracy that stamps out in the production use, often occur as flame quenching.The major cause that causes these situations is the moulding stock composition, organizational controls is improper and cause that the not enough situation of the last off-temper hardness of mould takes place.Therefore, it is most important for improving die life how to obtain high-quality car panel die material and die blank.

Summary of the invention

The purpose of this invention is to provide a kind of vehicle mould hard hollow alloy ball iron mould material and preparation method thereof.Another object of the present invention is to improve the Cr-Mo cast iron composition that existing tradition is used, and improves the service requirements of satisfying of the last quenching hardness of moulding stock.

A kind of vehicle mould of the present invention hard hollow alloy ball iron mould material is characterized in that having following chemical constitution (weight %):

C?3.5～3.8，Si?2.1～2.5，Mn?0.5～0.8，Cr?0.1～0.3，

Cu?0.8～1.0，Mo?0.4～0.6，Ni?0.2～0.4，P＜0.02，

S＜0.02, the Fe surplus

The preparation method of mentioned component moulding stock is characterized in that having following technological process and step:

A. form according to the materials chemistry of above-mentioned design and prepare burden, place medium-frequency induction furnace to carry out melting, smelting temperature is 1350～1450 ℃;

B. adopt surface heat to handle on the foundry goods that makes, Heating temperature is 850～950 ℃ of scopes, and the surface heat processing is carried out in the quenching quenching in air subsequently; Can adopt the frequency induction heating power supply, its frequency of utilization is 10-25KHz, and output rating is 20-28KW.

The chemical constitution of vehicle mould alloy ball iron moulding stock of the present invention, its foundation definite and design is as follows:

C is the basis that produces the high-carbon phase.The harmful effect that the graphite of its generation is concentrated the effect of isolating and the casting stress of matrix is less when part bears action of compressive stress, so the tensile strength of cast iron is higher, is applicable to be manufactured on the Drawing Die of working under the action of compressive stress.In addition, the existence of graphite has caused a large amount of interior breach, therefore, cast iron also has the insensitive characteristics of breach, and still along with the increase of C, the degree of graphitization of cast iron increases and becomes thick, perlite reduces and the ferrite increase, and hardness reduces, so C should be advisable at 3.5-3.8%.

Si promotes the graphited element of C, is dissolved in the ferrite, and ferritic intensity and hardness are improved, and plasticity is corresponding to decrease, but Si content can make mechanical property descend when higher, so be controlled at 2.1-2.5%.

Mn can be dissolved in ferrite and cementite, strengthen the bonding force of iron and carbon atom, thereby it is to hinder the element that greying promotes that carbide forms, and it is to stablize the perlite element, can improve intensity, hardness and wear resistance, can offset the deleterious effect of a part of S, but the Mn too high levels can make fragility increase with S chemical combination, the content of Mn should be considered according to the combined factors such as content of S in the original molten iron, be controlled at 0.5-0.8%.

Cu can reduce the susceptibility of cast iron to section, improves graphite form, promotes pearlitic formation, and refine pearlite, improves pearlitic microhardness, thereby increases the wear resistance of cast iron.Cu can improve toughness, improves solidity to corrosion and thermal conductivity, and share with Mn, Si to increase flowability, favourable cast molding, and energy refinement graphite, but the too high levels of Cu can produce hot cracking tendency, is advisable with 0.8-1.0%.

Cr is anti-graphitizing element, dwindles the γ district, help improving wear resistance and keep hot strength, and Cr can increase the hardening capacity of material, though effect not as Mn and Mo, cost benefit is very high.But Cr impels grain growth easily, and is the stable element of carbide, therefore is controlled at 0.1-0.3%.

Mo is a kind of strong hardening capacity additive, and energy refine pearlite and graphite are anticorrosive better with oxidation capacity, Mo energy stable carbide, and therefore reinforced ferrite is controlled at 0.4～0.6%.

Ni has slight graphitizing in cast iron, can be dissolved in liquid iron and austenite, reduces austenite transformation temperature, enlarge the austenitic area, refinement also increases perlite, and is hardening capacity additive preferably, can effectively improve low-temperature performance, but Ni is more expensive, therefore is controlled at 0.2～0.4%.

S and P are harmful element, and its content all should be controlled at bottom line, in order to avoid produce the adverse consequences that worsens cast iron, should make the content of P and S be lower than 0.02%.

The alloy ball iron moulding stock that the inventive method makes, its hardness of cast form are HB200-230, and the air quenching surface hardness is 60HRC, and depth of hardening zone surpasses 2.5mm, and its processing technology is stronger.It is applicable to the car panel die of high rigidity and high-wearing feature surface requirements fully.

The alloy ball iron material that the inventive method makes, the tensile strength of its single casting sample is at 520-580mg/mm ²In the scope.

Embodiment

After now embodiments of the invention being described in.

Embodiment 1

In the present embodiment, adopt the chemical constitution (weight %) of alloy ball iron material as follows:

C?3.7，Si?2.4，Mn?0.6，Cr?0.2，Cu?0.9，

Mo 0.5, and Ni 0.3, P＜0.02, S＜0.02, Fe surplus

Admixtion is put in the medium-frequency induction furnace melting, and smelting temperature is 1400 ℃.The foundry goods that makes, it is of a size of φ 60 * 150mm, as sample; Adopt the frequency induction heating installation to carry out hard surfacing then and handle, temperature is controlled at 850～950 ℃ of temperature ranges, and the type of cooling is air cooling, and frequency of utilization is 10-25KHz, and output rating is 20-24KW.

Behind surface induction hardening, test result, its surperficial average hardness is 60HRC, depth of hardening zone is 2.75mm.

Claims (2)

1. vehicle mould hard hollow alloy ball iron mould material is characterized in that having following chemical constitution and weight percentage is:

C 3.5～3.8，Si?2.1～2.5，Mn?0.5～0.8，Cr?0.1～0.3，

Cu 0.8～1.0, and Mo 0.4～0.6, and Ni 0.2～0.4, P＜0.02, S＜0.02, Fe surplus

2. a kind of vehicle mould as claimed in claim 1 is with the preparation method of hard hollow alloy ball iron mould material, and its feature has following technological process and a step dried:

A. form according to the materials chemistry of above-mentioned design and prepare burden, place medium-frequency induction furnace to carry out melting, smelting temperature is 1350～1450 ℃;

B. adopt surface heat to handle on the foundry goods that makes, Heating temperature is 850～950 ℃ of scopes, and the surface heat processing is carried out in the quenching quenching in air subsequently; Can adopt the frequency induction heating power supply, its frequency of utilization is 10-25KHz, and output rating is 20-28KW.