CN103088248A

CN103088248A - Formula of nodular cast iron used in automotive gear ring bracket

Info

Publication number: CN103088248A
Application number: CN2011103382663A
Authority: CN
Inventors: 张玉新
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-11-01
Filing date: 2011-11-01
Publication date: 2013-05-08

Abstract

The invention relates to a formula of nodular cast iron used in an automotive gear ring bracket. The nodular cast iron is prepared from the raw materials of, by weight, 3.75% of C, 2.65% of Si, 0.63% of Mn, no more than 0.023% of P, and no more than 0.018 of S. Compared with a product produced by using carbon structural steel, according to a product produced by using the product provided by the invention, a tensile strength is increased by more than 100N/mm<2>; a machining and cutting performance is increased by 25-30%; product cost is reduced by 15-20%; and weight loss of non-critical part is realized when the reduction of maximum stress is ensured, such that purposes of energy saving and emission reducing are achieved.

Description

The formula of the spheroidal graphite cast iron that the automobile gear ring support is used

Technical field: the formula that the present invention relates to the spheroidal graphite cast iron that the automobile gear ring support uses.

Background technology: present automobile gear ring support is all to adopt structural carbon steel; 45 steel tensile strength 〉=600 N/mm2, the actual tensile strength that detects is between 670-760; Part adopts 45 steel must pass through forging process, because metal is processed into tracing back property, and the chip removal difficulty; Part adopts forging, must be through heating, and blocking, rough forge, finish forge, metal heats repeatedly, and coarse grains easily produces slag inclusion, the scarce limit such as crackle.And Heavy Weight, the waste starting material can not reach the requirement of energy-saving and emission-reduction.

Summary of the invention: purpose of the present invention is exactly the formula that the spheroidal graphite cast iron that a kind of automobile gear ring support uses will be provided, and it can overcome the above problem that currently available products exists.The object of the present invention is achieved like this, and the formula of the spheroidal graphite cast iron that the automobile gear ring support is used is characterized in that: each raw materials by weight content is; C:3.75 %, Si:2.65 %, Mn:0.63%, P≤0.023, S≤0.018.

The advantage that the product that the present invention produces is compared with the product of structural carbon steel production:

1. 45 steel tensile strength 〉=600 N/ mm ², the actual tensile strength that detects is between 670-760; Spheroidal graphite cast iron QT700, tensile strength 〉=700 N/ mm ²; The actual tensile strength that detects is between 725-780.Tensile strength improves 100N/ mm ²Above.

2. the processing cutting ability improves 25%-30%;

45 steel forgings are because metal is processed into tracing back property, and chip removal is difficult.Spheroidal graphite cast iron QT700 metal is processed into fragility, and chip removal is easier, the not sticking cutter of iron filings, and therefore processing cutting ability can improve 25%-30%.

3. product cost reduces 15%-20%.

Part adopts forging, must be through heating, and blocking, the rough forge finish forge, metal heats repeatedly. and coarse grains easily produces slag inclusion, the scarce limit such as crackle.

Part adopts foundry goods, a cast molding, and the part homogeneous microstructure, the single-piece work efficiency is high, the corresponding reduction of product cost.

4. guarantee in situation that maximum stress reduces non-significant points loss of weight;

Compared with similar products, due to the uniform lightening hole that is provided with 25 millimeters of diameters more than six or six on spheroidal graphite casting blank large end face, it is heavy that pts wt alleviates 1.2Kg than like product, is optimized for 9.8-10.0kg from original single-piece weight 11.2kg, can save 1.2kg for every.

5, single products is saved starting material 1.2kg, both reduced the mark coal energy consumption of 8kg left and right, (at present the energy consumption of 1 ton of qualified ironcasting of domestic every production is 500-700kg mark coal), the quantity discharged 25kg left and right (China's 1 ton of forging of every production namely will give off the CO 2 waste gas thing of nearly 2 tons) of having reduced again the Litters such as carbonic acid gas in the Cast Iron Production smelting process.

6, calculate according to relevant international standard: vehicle weight often alleviates 10%, can improve fuel efficiency 8%; The Integral automobile quality often alleviates 10 kilograms, and when travelling 1 km, CO2 emissions just reduces by 1 gram.After new texture single product weight saving 1.2kg, every bogie bridge can alleviate 2.4kg, can in vehicle actual travel process, greatly improve the fuel rate of utilization, the CO2 emissions of decrease vehicle.

Embodiment:

The formula of the spheroidal graphite cast iron that the automobile gear ring support is used is characterized in that: each raw materials by weight content is; C:3.75 %, Si:2.65 %, Mn:0.63%, P≤0.023, S≤0.018.During concrete enforcement, add pig iron 400Kg in stove, foundry return 250 Kg, steel scrap 55 Kg, ferrosilicon 2.1 Kg, ferromanganese 2.5 Kg cover after fusing Si-Fe0.7Kg, Nodulizing agent 9.8-12Kg, composition content by weight percentage are controlled at C:3.6-3.75, Si:2.65-2.7, and detect with analyser, the spheroidal graphite cast iron after processing need carry out normalizing treatment, and the purpose of normalizing is in order to obtain pearlitic matrix body tissue, and crystal grain thinning, uniform formation is to improve the mechanical property of foundry goods.Sometimes normalizing is also that spheroidal graphite cast iron hard surfacing preparation, normalizing organizationally divides high temperature normalizing and cryogenic normalizing.The high temperature normalizing temperature generally is no more than 950～980 ℃, and cryogenic normalizing generally is heated to 820～860 ℃, common pack temperature interval.Generally also need temper after normalizing, the internal stress that produces during with the elimination normalizing.

In order to improve the mechanical property of spheroidal graphite cast iron, need carry out quench treatment, general foundry goods is heated to more than 30～50 ℃, quenches after insulation in oil, obtains martensitic stucture.In order suitably to reduce the unrelieved stress after quenching, should carry out tempering after customary quenching, low-temperaturetempering is organized as tempered martensite and adds residual bainite and add globular graphite again.This wear resistance of organizing is good, is used for requiring high-wearing feature, high-intensity part.The average tempering temperature is 350-500 ℃, is organized as tempering troostite after tempering and adds globular graphite, be applicable to require wear resistance good, have certain stability and elastic thick.The high tempering temperature is 500-60D ℃, is organized as tempered sorbite after tempering and adds globular graphite, has toughness and intensity in conjunction with good over-all properties, therefore widespread use aborning.

Claims

1.. the formula of the spheroidal graphite cast iron that the automobile gear ring support is used is characterized in that: each raw materials by weight content is; C:3.75 %, Si:2.65 %, Mn:0.63%, P≤0.023, S≤0.018.