Brass Silica Sol Investment Casting

Copper alloys with zinc as the main alloying element are commonly referred to as brass. The copper-zinc binary alloy is called ordinary brass, and the ternary, quaternary or multi-element brass composed of a small amount of other elements on the basis of copper-zinc alloy is called special brass.

After more than 20 years of precipitation, Qinhuangdao Zhongwei Precision Machinery Co., Ltd. has rich experience in the production of various grades of brass, tin bronze castings, silicon bronze, aluminum bronze and other castings. Manufacturers from various countries are expected to consult Brass Silica Sol Investment Casting.

Product Description

Brass Silica Sol Investment Casting Basic Information

1. Implementation standards: The company strictly implements ISO9001 & TS 16949 certification.

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

3. Main processes: sand casting, silica sol investment casting, water glass investment casting,shell casting,deburring, sand blasting, machining, heat treatment, leak testing, surface treatment, etc.

4. Available materials:

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. Customized according to customer requirements.

Product Performance

Cast brass is a cast alloy based on Cu-Zn binary alloy, which has a small crystallization temperature interval and good casting performance. Compared to tin bronze, cast brass has higher mechanical properties. In addition, the cost is lower because brass contains a large amount of zinc. These are the reasons why cast brass is widely used.

However, compared with tin bronze and aluminum bronze, cast brass has poor corrosion resistance. Due to the active chemical properties of zinc and the low electrode potential, brass is more susceptible to corrosion. Especially in seawater and other corrosive media with electrolytes, interphase current is generated between the copper-rich phase and the zinc-rich phase in the brass structure, which aggravates the corrosion of the zinc-rich phase with lower electrode potential, which is called dezincification. corrosion.

The solid solubility of zinc in brass is very large. About 37% of zinc can be dissolved in copper in the equilibrium state at room temperature, while about 30% of zinc can be dissolved in the actual production as-cast state. Therefore, zinc has a good solid solution strengthening effect in copper. Although ordinary brass has certain strength, hardness and good casting performance, it has poor wear resistance, corrosion resistance, especially corrosion resistance to flowing seawater, steam and inorganic acid. Therefore, a small amount of other alloying elements (mainly Mn, Al, Fe, Si, Pb, etc.) are usually added to cast brass to improve its mechanical, physical and chemical properties, thereby forming special cast brass that can meet various performance requirements. , such as free-cutting brass, naval brass, high-strength brass and die-cast brass.

The crystallization temperature range of brass is very small (about 30 ~ 40 ℃). When the zinc content increases, the liquidus temperature drops rapidly, and the melting point decreases. Therefore, brass has good fluidity and forms concentrated shrinkage cavities. , it is not easy to form loose and intragranular segregation. The melting point of brass is low, and it contains a large amount of zinc, which is easy to evaporate. When it evaporates, it can prevent the alloy from inhaling and take away the gas in the copper liquid, so that there is less inhalation during the smelting process. Therefore, brass castings generally do not produce stomata. At the same time, when smelting brass, zinc itself has a strong deoxidizing effect, and no other deoxidizing agent is needed. Therefore, brass is easier to smelt than other copper alloys and has better casting properties. Due to the high affinity of zinc and oxygen, the oxide ZnO is easily formed during the smelting process of brass. However, it is different from Al2O3 and is easily separated into slag from the copper liquid. As long as measures are taken to prevent secondary oxidation of the alloy, oxidation inclusion defects can generally be avoided. . Brass has a large shrinkage rate, and it is easy to form concentrated shrinkage holes during solidification. Therefore, larger feeding risers can be set according to the principle of sequential solidification. Brass has the characteristics of shell-like solidification and is less sensitive to casting cooling rate, so its mechanical properties are less sensitive to changes in casting wall thickness.

In casting production, binary brass is almost not used. In order to meet special performance requirements and improve casting process performance, multi-component brass casting parts are widely used.

Quality Control

1. Chemical composition of Brass Silica Sol Investment Casting

Brass is a Cu-Zn binary alloy with zinc as the main alloying element, commonly known as brass or ordinary brass. Ordinary brass has certain strength, hardness and good casting properties, but poor wear resistance, corrosion resistance, especially corrosion resistance to flowing seawater, steam and inorganic acid. Various alloying elements can usually be added to improve the mechanical, physical and chemical properties of brass, resulting in special brasses suitable for different environments, such as naval brass, free-cutting brass, high-strength manganese brass and die-casting yellow copper etc.

2. Casting process

Casting brass alloys have some differences in melting point, fluidity, solidification shrinkage, melt sensitivity to gas, volatility and hot cracking tendency, so the applicable casting methods are also different.

The casting methods of casting brass mainly include die casting, sand casting, centrifugal casting, continuous casting and investment casting. Different alloys require targeted selection.

The casting properties of cast brass are as follows: zinc in cast brass is the main factor affecting the casting properties of cast brass. The vaporization point of zinc is about 907°C, and the melting point of cast brass is about 900°C. , zinc has a great tendency to evaporate and oxidize. Casting brass has good fluidity, but manganese brass shrinks greatly, which is prone to shrinkage, cold cracking, deformation and other problems.

In view of the above characteristics, the following technological measures should be taken during casting:

1) Choose sand cores with good concessions to reduce casting stress and prevent cracks and deformation.

2) Set the riser to strengthen the feeding.

3) The setting of the gating system should ensure the realization of directional solidification, the structure of slag collection and slag blocking should be set up, and the liquid flow should be filled smoothly. The layout of the inner runner should make the castings cool evenly.

4) The pouring process minimizes the pouring temperature of the cast brass to reduce liquid shrinkage and prevent vaporization.

Compared with bronze, the solid solubility of zinc in copper is very large. Under normal temperature equilibrium, about 37% of zinc can be dissolved in copper, and about 30% of zinc can be dissolved in as-cast state, while tin bronze In the as-cast state, the solid solubility mass fraction of tin in copper is only 5% to 6%, and the solid solubility mass fraction of aluminum bronze and aluminum in copper is only 7% to 8%. Therefore, zinc has a high concentration in copper. Good solid solution strengthening effect, at the same time, most alloying elements can also be dissolved in brass to varying degrees, further improving its mechanical properties, thus making brass, especially some special brass, have the characteristics of high strength, the price of zinc It is lower than aluminum, copper and tin, rich in resources, and the amount of zinc added in brass is more, so the cost of brass is lower than that of tin bronze and aluminum bronze. The solidification temperature range of brass is very small, the fluidity is good, and the melting is convenient. Because brass has the above characteristics of high strength, low price and good casting performance, brass has more varieties, larger output and wider application than tin bronze and aluminum bronze in copper alloys. However, the wear resistance and corrosion resistance of brass are not as good as those of bronze, especially the corrosion resistance and wear resistance of ordinary brass are relatively low. Only when some alloying elements are added to form various special brass, its wear resistance and wear resistance Corrosion performance is improved and enhanced.

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

Cast Brass Brass used to produce castings. Brass Silica Sol Investment Casting is widely used in machinery manufacturing, ships, aviation, automobiles, construction and other industrial sectors. It occupies a certain amount of heavy non-ferrous metal materials and forms cast brass series.