CN101125359A - Method for die casting magnesium alloy through improving normal die casting machine to magnesium alloy die casting machine - Google Patents

Abstract

The present invention relates to a method for reforming common casting press into magnesium alloy costing press in order to cast magnesium alloy by die.The diameter of a punching head is computed by formula(1), d2=(n/V)d1n=2.5 to 3.1, herein, d1 is initial diameter of punching head in the casting press, d2 is the diameter of punching head after reformation, V is shooting speed of the casting press. The use method of the invention is computed in formula(2), t=0.0346((tm-tf+2.5S)/(tf-td) Delta, wherein, t is filling time, tm is casting temperature, tf is the minimal flow termerature, td is preheating temperature of casting mold, S is the maximal solid content during continuous casting and Delta is average wall thickness of cast. The average temperature of casting is 650 DEG C to 690 DEG C and the preheating temperature of casting mold is 180 DEG C to 240 DEG C. The present invention has low procution cost and convenient operation.

Description

A kind of method that common die casting machine is transformed into the magnesium alloy pressure casting machine diecast magnesium alloy

Technical field

The present invention relates to the die-casting technique of magnesium alloy, a kind of method that common die casting machine is transformed into the magnesium alloy pressure casting machine diecast magnesium alloy is provided especially.

Background technology

Die casting is the abbreviation of compression casting, its essence is under the effect of high pressure, and the metal that makes liquid state or semi liquid state is with higher speed filling die-casting die die cavity, and solidifies under pressure and obtain the method for foundry goods.

Die casting is one of state-of-the-art metal forming process, is to realize few smear metal, and the effective way of chipless is used very extensively, develops very fast.Extrusion process is not only applicable to non-ferrous metal such as zinc, aluminium, magnesium and copper, and is used for die casting cast iron and steel-casting.The size of die casting and weight depend on the power of die casting machine.Because the power of die casting machine constantly increases, casting dimension can be from several millimeters to 1～2 meter; Weight can restrain tens of kilograms from several.Die casting also no longer is confined to auto industry and measurement instrument industry, progressively expand other each industrial department to, as tens industries such as agricultural machinery, machine tool industry, electronics industry, national defense industry, computer, medicine equipment, clock and watch, camera and haberdashery and hardware.The new technologies such as application that aspect die-casting technique, occurred evacuated die-casting process, oxygenation die casting, smart fast close die casting and soluble core again.

At present, countries in the world are very good to the application prospect of magnesium alloy die casting, particularly in automobile, aviation, telecommunications, communications and transportation and mechanical industry, adopt Mg alloy castings replacement aluminium alloy or iron and steel parts can alleviate machinery weight effectively, thereby save energy consumption significantly, reduce environmental pollution.As automobile if whenever alleviate 100kg, then every kilometer fuel consumption can reduce 0.4L, so now developed countries such as U.S., day, Europe begin the application of expansion Mg alloy castings on automobile, as engine cylinder-body, gear-box, crankcase, enter steam discharge liquid pipe, wheel hub, chassis etc.Make Mg alloy castings with annual 20%～30% speed increment, wherein 80% is die casting.Magnesium alloy die casting enlarges equally day by day in the application of industries such as household electrical appliances light industry and haberdashery and hardware, as laptop computer shell, recording playback cabinet, mobile telephone set, electric tool shell, and camera body, upholstery, mowing casing etc.These magnesium alloy die castings not only weight alleviate greatly, and size is precise and stable, and any surface finish, have a series of outstanding advantages.According to foreign statistic, reach more than 20 ten thousand tons to the annual production of magnesium alloy die casting in 2006, increased by 40% than 1996.Therefore, magnesium alloy pressure-casting and magnesium alloy pressure casting machine are just becoming one of important brainstorm project in the world today.Yet magnesium alloy pressure-casting technology remains in some problems, has limited the expansion of its application.Because the thermal capacitance of magnesium alloy is less, latent heat of solidification is little, and process of setting has a great difference with traditional aluminium alloy and zinc alloy diecasting, needs higher filling velocity could guarantee that magnesium alloy fills type in the short period of time and solidifies in press casting procedure.But because the hysteresis of domestic magnesium alloy pressure-casting industry, a lot of enterprises still are engaged in magnesium alloy pressure-casting with common die casting machine, and common die casting machine is because the restriction of injection speed, thus the die casting of producing not only quality have problems, and very easily bring out accident.In order to solve common die casting machine because the slow problem of bringing of injection speed is domestic the die casting machine manufacturer production has been arranged is used for the special-purpose die casting machine of magnesium alloy.But price is more much higher than common die casting machine, and production cost is improved, and is very undesirable.

Summary of the invention

At the prior art weak point, the objective of the invention is to provide a kind of method that common die casting machine is transformed into the magnesium alloy pressure casting machine diecast magnesium alloy, what improved die casting function realized flow such as low speed carries out die casting to mold cavity, casting back foundry goods is protected full, no steam bubble and flaw meet processing request.

The technical solution adopted for the present invention to solve the technical problems is that the punch diameter of existing common die casting machine is complied with

$d_2=\frac{n}{\sqrt{V}}{d}_1,n=2.5~3.1---\left(1\right)$

Mechanical relation transform.

In the formula: d ₁Be the former punch diameter of die casting machine; d ₂Be improved die casting machine punch diameter; V is the injection speed of die casting machine.

Die casting machine is through after increasing the punch diameter transformation, and when producing magnesium alloy die casting, the filling time of liquid magnesium alloy and pouring temperature and casting mold preheat temperature satisfy following empirical equation:

t＝0.0346((t _m-t _f+2.5S)/(t _f-t _d))δ (2)

The t----filling time;

t _m---pouring temperature;

t _f---minimal flow temperature;

t _d---casting mold preheat temperature;

The solid block content of the uninterrupted cast of S---maximum;

δ---foundry goods average wall thickness.

When actual production, pouring temperature is 650 ℃～690 ℃, and the casting mold preheat temperature is 180 ℃～240 ℃.When die casting machine is transformed, n value in (1) formula is taken off in limited time, (2) filling time that allows in the formula is longer, pouring temperature and casting mold preheat temperature are answered capping, opposite when the n value capping in (1) formula, (2) filling time that allows in the formula is shorter, and pouring temperature and casting mold preheat temperature should be taken off limit.

Common die casting machine is through after the technological transformation, and injection speed can reach 6～10m/s.

Can realize die casting in short-term by the punch diameter that increases common die casting machine, reach goal of the invention, realize the invention effect.

Good effect of the present invention is: foundry goods is protected full, and no steam bubble and flaw meet processing request, and production cost is low, need not to acquire special-purpose die casting machine and can produce qualified product.

The specific embodiment

The punch diameter of common die casting machine is complied with

$d_2=\frac{n}{\sqrt{V}}{d}_1,n=2.5~3.1---\left(1\right)$

Transform, in the formula: d ₁Be the former punch diameter of die casting machine; d ₂Be improved die casting machine punch diameter; V is the injection speed of die casting machine.

When producing magnesium alloy die casting, pouring temperature is 650 ℃～690 ℃, and the casting mold preheat temperature is 180 ℃～240 ℃.

Its specific embodiment such as example 1: when common die casting drift adds XXXmm than drift increasing diameter before transforming, be AM60B to the magnesium alloy trade mark, its composition is as shown in table 1.

The chemical composition of table 1AM60B alloy

Element	Al	Zn	Mn	Si	Cu	Ni	Fe	Mg
									Content	5.6-6.4	≤0.2	0.26-0.5	≤0.05	≤0.008	≤0.001	≤0.004	All the other

Carry out die casting.Its die-casting technological parameter is: 665 ℃ of pouring temperatures, and 180 ℃ of mold preheating temperatures, the dwell time is 8s, operating pressure 80MPa, ingate speed 60m/s, 550 tons of die casting machine engineering pressures.

As example 2: when common die casting drift adds XXXmm than drift increasing diameter before transforming, with the magnesium alloy trade mark is AM60B, the same table of its chemical composition is produced notebook computer casing, its die-casting technological parameter is: 665 ℃ of pouring temperatures, 250 ℃ of mold preheating temperatures, injection speed 5m/s, filling velocity 70m/s, 650 tons of die casting machine engineering pressures.

Claims (3)

1. one kind is transformed into the method for magnesium alloy pressure casting machine diecast magnesium alloy with common die casting machine, and it is characterized in that enlarging punch diameter and calculate by (1) formula,

$d_2=\frac{n}{\sqrt{V}}{d}_1$ n＝2.5～3.1 (1)

Wherein: d ₁Be the former punch diameter d of die casting machine ₂Be improved die casting machine punch diameter; V is the injection speed of die casting machine.

2. one kind is transformed into the method for magnesium alloy pressure casting machine diecast magnesium alloy with common die casting machine, it is characterized in that filling time and pouring temperature and casting mold preheat temperature, and its value is determined by (2) formula:

t＝0.0346((t _m-t _f+2.5S)/(t _f-t _d))δ (2)

The t----filling time;

t _m---pouring temperature;

t _f---minimal flow temperature;

t _d---casting mold preheat temperature;

The solid block content of the uninterrupted cast of S---maximum;

δ---foundry goods average wall thickness;

Wherein pouring temperature is elected 650 ℃～690 ℃ as, and the casting mold preheat temperature is elected 180 ℃～240 ℃ as.

3. according to the described a kind of method that common die casting machine is transformed into the magnesium alloy pressure casting machine diecast magnesium alloy of claim 1 to 2, the n value that it is characterized in that working as in (1) formula is taken off in limited time, (2) filling time that allows in the formula is longer, pouring temperature and casting mold preheat temperature are answered capping, opposite when the n value capping in (1) formula, (2) filling time that allows in the formula is shorter, and pouring temperature and casting mold preheat temperature should be taken off limit.