CN105256237A - A kind of high-chromium anti-corrosion high-precision pre-hardened plastic mold steel and its preparation method - Google Patents

Abstract

The invention discloses a high-chromium corrosion-resistant high-precision pre-hardened plastic die steel and a preparation method thereof, the die steel properly improves the proportion of elements such as Cr, Mn, Zn, Y and the like on the element proportion of the traditional pre-hardened plastic die steel, simultaneously controls the dosage of other alloy elements, further improves the mechanical property and the processing property of alloy materials on the basis of ensuring the mechanical property of the traditional plastic die steel, has good thermal stability and good die size stability, can obtain a plastic part with higher precision, and added rare earth oxide-graphene oxide coated nano tungsten carbide composite modifier refines the organizational structure of the die steel, improves the interface compatibility among crystals, has obvious reinforcing and toughening effects and uniform and stable modification effects; the die steel has compact surface, wear resistance, corrosion resistance, durability, simple and efficient preparation method, short manufacturing period and high production and application value.

Description

A kind of high-chromium anti-corrosion high-precision pre-hardened plastic mold steel and its preparation method

technical field

The invention relates to the technical field of plastic mold steel products, in particular to a high-chromium anti-corrosion high-precision pre-hardened plastic mold steel and a preparation method thereof.

Background technique

With the rapid development of automobiles, tractors, motors, radios, household appliances and national defense industries, non-cutting processes such as cold stamping, extrusion, die forging and die-casting are widely used, and the demand for molds is increasing. There are also higher and higher requirements for the steel types of the mold, the metallurgical production of the steel and the heat treatment quality of the steel.

At present, the types of die steel mainly include cold work die steel, hot work die steel, plastic die steel, etc., among which plastic die steel accounts for the largest proportion, and the performance of die steel is directly related to the quality of processed plastic products. The characteristics of plastic products have high requirements for plastic mold steel in terms of corrosion resistance, dimensional stability, surface wear resistance, and polishing. The existing plastic mold steel mainly has low hardness, poor wear resistance, and the use of Low service life, many surface defects and other problems to be solved.

Contents of the invention

The purpose of the present invention is to provide a high-chromium anti-corrosion high-precision pre-hardened plastic mold steel and a preparation method thereof in order to make up for the defects of the prior art.

The present invention is achieved through the following technical solutions:

A high-chromium corrosion-resistant high-precision pre-hardened plastic mold steel. The weight percentages of the components in the mold steel are: C: 0.3-0.4%, Si: 0.5-0.6%, Cr: 10.5-12.0%, Mn: 3.2-3.6%, Zn: 2.5-3.0%, Y: 0.5-0.8%, Ta: 0.03-0.08%, P≤0.02%, S≤0.01%, compound modifier: 0.01-0.02%, the rest is Fe and not Avoid impurities.

The high-chromium anti-corrosion high-precision pre-hardened plastic mold steel, the composite modifier is made of the following raw materials in parts by weight: nano-rare earth oxide 2-3, nano-titanium carbide 8-10, graphite oxide ene 1-1.5, appropriate amount of absolute ethanol, PEG-4000.1-0.2; the preparation method is: first dissolve PEG-400 in absolute ethanol, then add nano-rare earth oxide and graphene oxide, and ultrasonically stir for 40-50min , after it is completely dispersed, add nano-titanium carbide, continue ultrasonic stirring and mixing for 1-2 hours, and dry it in an oven at 350-400°C after the stirring is completed. After complete drying, the powder is fully ground and dispersed to obtain rare earth oxide-graphene oxide Composite modificator coated with nano-titanium carbide.

The preparation method of a high-chromium anti-corrosion high-precision pre-hardened plastic mold steel, the preparation method is:

(1) Put all the raw materials except the composite modifier into the melting furnace according to the ratio of elements, the molten steel obtained after complete melting is refined and vacuum degassed and poured into steel ingots, and the composite modifier is added along with the flow during the pouring process;

(2) Heat the obtained steel ingot to 1050-1110°C at a heating rate of 80-100°C/h in a heating furnace, and then forge the steel ingot after holding for 3-4 hours. The forging start temperature is 1000-1080°C and the forging stop temperature 750-800°C, the obtained modules are cooled naturally after being released from the furnace;

(3) Put the module obtained in step (2) into a tempering furnace, heat it to 450-500°C at a rate of 60-80°C/h, keep it warm for 4-5h, then take it out of the furnace, and cool it naturally to room temperature.

The advantages of the present invention are: the present invention properly increases the ratio of Cr, Mn, Zn, Y and other elements in the ratio of elements of traditional pre-hardened plastic mold steel, and at the same time controls the amount of other alloy elements, ensuring the stability of traditional plastic molds. On the basis of the mechanical properties of steel, the mechanical properties and processing properties of the alloy material are further improved. It has good thermal stability, good dimensional stability of the mold, and can obtain higher-precision plastic parts. The added rare earth oxide-graphene oxide Coated nano-tungsten carbide composite modifier refines the structure of the mold steel, improves the interfacial compatibility between crystals, has a significant effect of strengthening and toughening, and has a uniform and stable modification effect; the surface of the mold steel is compact, wear-resistant and corrosion-resistant, and durable Durable, the preparation method is simple and efficient, the production cycle is short, and the production and application value is extremely high.

detailed description

The percentage by weight of each component in the die steel of this embodiment is: C: 0.3%, Si: 0.5%, Cr: 10.5%, Mn: 3.2%, Zn: 2.5%, Y: 0.5%, Ta: 0.03%, P≤0.02%, S≤0.01%, compound modifier: 0.01%, the rest is Fe and unavoidable impurities.

Wherein the composite modificator is made of the following raw materials in parts by weight: nano-rare earth oxide 2, nano-titanium carbide 8, graphene oxide 1, appropriate amount of absolute ethanol, PEG-4000.1; its preparation method is: first dissolve PEG-400 in Add nano-rare earth oxides and graphene oxide to absolute ethanol, and ultrasonically stir for 40 minutes. After they are completely dispersed, add nano-titanium carbide and continue ultrasonically stirring for 1 hour. After stirring, dry them in an oven at 350°C. After drying, the powder is fully ground and dispersed to obtain a composite modificator in which rare earth oxide graphene oxide is compositely coated with nano-titanium carbide.

The preparation method of this embodiment mold steel is:

(1) Put all the raw materials except the composite modifier into the melting furnace according to the ratio of elements, the molten steel obtained after complete melting is refined and vacuum degassed and poured into steel ingots, and the composite modifier is added along with the flow during the pouring process;

(2) Heat the obtained steel ingot to 1050°C at a heating rate of 80°C/h in a heating furnace, and then forge the steel ingot after holding the temperature for 3 hours. Natural cooling standby;

(3) Put the module obtained in step (2) into a tempering furnace, heat it up to 450°C at a rate of 60°C/h, keep it warm for 4 hours, take it out of the furnace, and cool it naturally to room temperature.

The mechanical property detection result of the plastic mold steel that the present embodiment prepares is as follows:

Test items measured value Hardness (HRC) 60.4 Tensile strength (MPa) 1582.4 Impact toughness (J/cm ² ) 158.1 Fracture toughness (MPa.m ^1/2 ) 146.7

Compared with the traditional P20 forged plastic mold steel, the plastic mold steel prepared in this example has an average service life of 2.5 times longer, has fewer surface defects, and has a surface roughness Ra<0.10 μm after polishing, and the obtained plastic parts have higher precision.

Claims (3)

1. A high-chromium anti-corrosion high-precision pre-hardened plastic mold steel is characterized in that the weight percentages of each component in the mold steel are: C: 0.3-0.4%, Si: 0.5-0.6%, Cr: 10.5 -12.0%, Mn: 3.2-3.6%, Zn: 2.5-3.0%, Y: 0.5-0.8%, Ta: 0.03-0.08%, P≤0.02%, S≤0.01%, compound modifier: 0.01-0.02% , and the rest are Fe and unavoidable impurities. 2. A kind of high-chromium corrosion-resistant high-precision pre-hardened plastic mold steel as claimed in claim 1, is characterized in that: described composite modificator is made of the following raw materials by weight: nano rare earth oxide 2-3 , nano-titanium carbide 8-10, graphene oxide 1-1.5, an appropriate amount of absolute ethanol, PEG-4000.1-0.2; the preparation method is: first dissolve PEG-400 in absolute ethanol, and then add nanometer rare earth oxide, Graphene oxide, ultrasonic stirring treatment for 40-50min, after it is completely dispersed, add nano-titanium carbide, continue ultrasonic stirring and mixing for 1-2h, after the stirring is completed, dry it in an oven at 350-400°C, and the powder is fully ground after complete drying Disperse to obtain a composite modifier of rare earth oxide-graphene oxide composite coating nano-titanium carbide. 3. the preparation method of a kind of high chromium anti-corrosion high-precision pre-hardened plastic mold steel as claimed in claim 1, is characterized in that, described preparation method is: (1) Put all raw materials except the composite modifier into the melting furnace according to the ratio of elements, and pour the molten steel obtained after complete melting into steel ingots after refining and vacuum degassing, and add the composite modifier along with the flow during the pouring process; (2) Heat the obtained steel ingot to 1050-1110℃ at a heating rate of 80-100℃/h in a heating furnace, and forge the steel ingot after holding for 3-4 hours. The forging start temperature is 1000-1080℃, and the forging stop temperature is 750-800°C, the obtained modules are cooled naturally after being released from the furnace; (3) Put the module obtained in step (2) into a tempering furnace, heat it to 450-500°C at a rate of 60-80°C/h, keep it warm for 4-5h, and then take it out of the furnace, and cool it naturally to room temperature.