Zinc Alloy Low Pressure Die Casting

Design and development of Zinc Alloy Low Pressure Die Casting mold A good die-casting product does not need a good die-casting machine. It must be the combination of the mold, the die-casting machine and the die-casting process to make a good product. The product characteristics of zinc alloy die castings are as follows:

1. The specific gravity is large, the weight is more textured, and it is stronger than plastic injection molding.

2. Good casting performance, it can die-cast precision parts with complex shapes and thin walls, and the surface of the castings is smooth.

3. Surface treatment is available: electroplating, spraying, painting.

4. It does not absorb iron during melting and die-casting, does not corrode the molding, and does not stick to the mold.

5. It has good mechanical properties and wear resistance at room temperature.

6. Low melting point, melting at 385℃, easier to form than aluminum alloy die casting.

Product Dsecription

1. Implementation standards: the company strictly implements ISO9001, ISO14001, IATF16949 certification

The products have passed the certification of ROHS, FDA EU, etc.

2. Product material standards: ISO, GB, ASTM, SAE, ISO, EN, DIN, JIS, BS

3. Main processes: die casting process, investment casting, shell casting, deburring, sand blasting, machining, heat treatment, leak testing, surface treatment, etc.

4. Casting available materials:

Magnesium alloy, aluminum alloy, zinc alloy, tin bronze, silicon bronze, aluminum bronze, brass, red copper, titanium alloy, high manganese steel, high chromium steel, high nickel steel, carbon steel, alloy steel, stainless steel, gray iron, , cast iron, cast steel, cast aluminum, etc. are customized according to customer requirements.

Available materials for die casting:

In the past, the raw materials of Zinc Alloy Low Pressure Die Casting mainly included No. 2, 3, 4, 5, and No. 7 alloys. At present, zinc alloy die-casting is mostly used for No. 3 zinc alloy. Later, there were high aluminum-based alloys ZA-8, ZA-12, ZA-27, wrought zinc alloys Zn-1Cu-0.1T and Zn-22AI alloys. Zinc alloy mainly contains aluminum, copper, magnesium, cadmium, lead, titanium and other elements, among which effective alloying elements: aluminum, copper, magnesium; harmful impurity elements: lead, cadmium, tin, iron. (Zinc alloys are also known as zinc-based alloys, and are generally divided into _ element alloys, ternary alloys and multi-element alloys. Binary zinc-based alloys generally refer to zinc-aluminum alloys; ternary zinc-based alloys generally refer to zinc-aluminum-copper alloys; multi-element zinc-base alloys generally refer to zinc-aluminum-copper alloys. Alloy - generally refers to zinc, aluminum, copper and other trace metals).

Melting process

Zinc Alloy Low Pressure Die Casting has the characteristics of small crystallization temperature range, low melting point, easy filling and molding, not easy to produce loose, not easy to produce mold sticking, and can prolong the life of die casting mold.

Zinc alloy die-casting has high mechanical properties, and can die-cast various complex and thin-walled castings.

Zinc alloys will shrink in size after being die-casted into castings, and the alloy composition has a great influence on the dimensional changes. The dimensions of zinc alloy castings without copper are relatively stable, and the dimensional changes of general zinc-aluminum alloy castings are not large.

The working range of zinc alloy is narrow. When the temperature is lower than 0 °C, its impact toughness decreases sharply, and when the temperature exceeds 100 °C, the mechanical properties decrease significantly.

Zinc alloy is easy to age, and the aging phenomenon is manifested as volume expansion, strength reduction, and plasticity reduction. The main reason is that the solubility of impurities such as lead, tin and cadmium in zinc is too small. Therefore, the impurity content should be strictly controlled during material selection and smelting.

Chemical composition and mechanical properties of die-casting zinc alloy (GB/T13818-92), the alloy code in the national standard consists of the letters "Y", "X" (the first letter of the Chinese pinyin of "pressure" and "zinc") and the following 3-digit Arabic numerals. The first two digits after YX represent the nominal percentage content of chemical element aluminum in the alloy, and the third number represents the nominal percentage content of chemical element copper in the alloy.

The role and influence of zinc alloy die-casting elements

In the alloy composition, the effective elements are aluminum, copper, and magnesium; the harmful elements are lead, cadmium, tin, and iron.

(1) The role of alloying elements

1) Aluminum is the main alloying element in zinc alloys, which can greatly improve the fluidity of zinc liquid, thereby improving its casting properties. The eutectic alloy with 5% aluminum has the best flow, but the impact strength is low. Aluminum in the range of 3.9% to 4.3%, on the one hand, strengthens the alloy, effectively refines the grains, and improves the strength; on the other hand, it can make the alloy have better casting properties. Aluminum has the effect of grain refinement and solid solution strengthening, which can reduce the reaction rate of zinc and iron. When the aluminum content exceeds 4.3%, the alloy becomes brittle and the casting is difficult to process; when the aluminum content is less than 3.9%, the forming of thin-walled parts is difficult, and there is a possibility of cooling crack after casting.

2) The role of magnesium is to reduce intergranular corrosion, refine the structure of zinc alloy, improve the wear resistance of zinc alloy, increase strength,

hardness. Generally controlled within the range of 0.03%~0.08%, more than 0.08% is prone to hot brittleness, hot cracking, and fluidity decline.

3) Copper can improve the strength, hardness, wear resistance and corrosion resistance of the alloy. When the copper content exceeds 1.25%, the casting size is unstable and the fluidity of the alloy is reduced.

4) Lead is distributed as fine spherical particles or surface film between grain boundaries and dendrites, causing intergranular corrosion.

5) Tin and zinc form a low melting point (198°C) eutectic, which causes intergranular corrosion to reduce toughness and cause hot embrittlement.

6) Cadmium exists in solid solution. Causes hot brittleness, and reduces corrosion resistance and fluidity, causing intergranular corrosion.

7) Iron and zinc form compounds, forming hard spots in die castings, affecting processing and electroplating polishing. In addition, iron also reacts with aluminum to produce FeAl and dross, resulting in a decrease in the aluminum content of the casting.

(2) Harmfulness of impurity elements lead, tin and cadmium

Lead, tin and cadmium are impurity elements in zinc alloys and must be controlled within the standard (0.004%). If the lead and tin exceed the standard (0.007%), it will not affect the product and cause electroplating blistering in a short time. However, the products returned from electroplating will slowly foam after being stored for a period of time. If the lead and tin elements exceed the standard by ten or several times, the extruded castings will be hot cracked, broken, and blackened. After polishing, the surface will be pitted, and intergranular corrosion will occur inside, resulting in blistering after electroplating.

The selection of zinc alloy for electroplating products is a key part. Alloy electroplating products are absolutely not allowed to exceed lead and tin standards. Be sure to control the return of the nozzle material to the furnace, and the return of the electroplating waste to the furnace brings in the impurity elements lead, tin and cadmium.

Post Casting Process

1. Heat treatment: annealing, carbonization, tempering, quenching, normalizing, surface tempering

2. Processing equipment: CNC, WEDM, lathe, milling machine, drilling machine, grinder, etc.;

3. Surface treatment: powder spraying, chrome plating, painting, sandblasting, nickel plating, galvanizing, blackening, polishing, bluing, etc.

Moulds and Inspection Fixtures

1. Mold service life: usually semi-permanent. (except for lost foam)

2. Mold delivery time: 10-25 days, (according to product structure and product size).

3. Tooling and mold maintenance: Zhongwei is responsible for precision parts.

Quality Control

1. Quality control: the defective rate is less than 0.1%.

2. Samples and trial run will be 100% inspected during production and before shipment, sample inspection for mass production according to ISDO standards or customer requirements

3. Testing equipment: flaw detection, spectrum analyzer, golden image analyzer, three-coordinate measuring machine, hardness testing equipment, tensile testing machine;

4. Provide after-sales service.

5. The quality can be traced back.

Application

Zinc Alloy Low Pressure Die Casting has excellent surface quality and has been widely used in the manufacture of toys, tableware, locks, hardware decorative parts, electrical and electronic castings, bathroom accessories, auto parts, zippers, metal buckles, watch cases, fans, Daily necessities, household appliances, photographic equipment, audio, mechanical and electrical products and parts.

Company Profile

Qinhuangdao Zhongwei Precision Machinery Co., Ltd. was established in 1997. The company is located in Qinhuangdao, a coastal city where Qin Shihuang seeks immortality and enters the sea. The company currently has more than 10 cold chamber die casting machines of 200T-1250T models, and a total of 3 hot chamber die casting machines of 88T-168T models. Mold development and then die-casting production to scraping, tapping, grinding, CNC, polishing, machining, laser engraving, powder spraying, oil spraying, electroplating, electrophoresis and other one-stop services. The excellent quality has created the reputation of gold, and the products of the other side have quickly become famous at home and abroad. More than 70% of the products are exported to the United Kingdom, Germany, Japan, the United States, Taiwan and other countries and regions.

Certicifation