Surface Treatment Technology - Chemical Methods

Chemical method for surface treatment in powder metallurgy process is using interaction of chemical substances to form a coating layer on the surface. This method is not current effect,. Its main method is:

(1)   chemical conversion treatment

In electrolyte solution, the interaction of chemical substance and product make product surface form a coating, which is called chemical conversion treatment.  Such as bluing, phosphating, passivation and chrome -pickle treatment.

(2) Chemical plating

In electrolyte solution, catalyzing product surface without external current, as a result of chemical reduction, some material was deposited on product’s surface to form coating, which is known as chemical plating. such as chemical nickel plating, electroless copper plating etc.

Original article link：

http://www.zcmim.com/article/powder-metallurgy-process-sttcm_1.html

Powder Metallurgy Process—Pouring Gate in Mould

powder metallurgy process

Definition of pouring gate in mould for powder metallurgy process （http://www.zcmim.com/）:  pouring gate is also called  feeding throat or inner sprue. It is a narrow part between the runner and product, also known as the shortest part in gating system.ong
Pouring gate role in powder metallurgy process: can  speed up the rapid of melting material transporting from runner to be a ideal and order flow and filled with cavity quickly; at the same time, pouring gate  also  play the role of closing  cavity to prevent from reverse liquid;  make separating  products from gating easier after molding.

Original article link：http://www.zcmim.com/article/powder-metallurgy-process-pmp_1.html

What are the disadvantages of powder metallurgy process?

What are the disadvantages of powder metallurgy process? Today let ZCMIM powder metallurgy manufacturer to explain it to you!

1) the inside of the product has a total pore;

(2) the strength of ordinary powder metallurgy products is lower than that of the corresponding forging or casting (about low 20%~30%);

3) due to the forming process of powder flow is far less than the liquid metal, so the product structure and shape of a certain limit;

4) the pressure needed to press forming is high, so the products are limited by the ability of the pressing equipment;

5) high pressure die cost, is generally only suitable for mass production or mass production.

Powder injection molding process

Powder injection molding process is using metal powder as raw materials, such as stainless steel, iron, low alloy steel, the use of powder metallurgy technology to manufacture various structural parts, powder metallurgy parts is in the mold production out of, so parts of the contour and the consistency of shape and size are very good, by way of removing sintering binder.

What is the requirement of powder metallurgy injection molding process for organic binder?

Powder metallurgy injection molding process of metal powder particle size is generally in 0.5~20 mu m; theoretically speaking, the smaller the particle size, the larger the surface area, easy forming and sintering. The traditional powder metallurgy process uses more than 40 m of coarse powder. The role of organic adhesive is to bond metal powder particles, so that the mixture in the jet barrel heating with rheological properties and lubrication, that is, to drive the flow of powder carrier. Therefore, the choice of adhesive is the carrier of the whole powder.

Requirement of powder metallurgy injection molding process for organic binder:

1 less dosage, with less adhesive agent can make better rheological properties of the mixture;

2 does not react, in the process of removing the adhesive and metal powder can not afford any chemical reaction;

3 easy to remove, no residual carbon in the inner. Mixing metal powder with organic binder mixed together, so that a variety of raw materials into a mixture of spray forming. The uniformity of the mixture has a direct impact on its mobility, which influences the spray forming process parameters, as well as the density and other properties of the final materials. The process of spray forming is consistent with the principle of plastic injection molding process, and the equipment condition is basically the same.

ZCMIM talk about powder metallurgy powder quality control from production process

Not metal powder manufacturer, we just hope that through the introduction of metal powder quality control to let more people be familiar with metal powder metallurgy process (i.e., metal powder injection molding), enhance  acknowledge of metal injection molding process.

1.      Strict raw materials and process control

Ø  choose domestic refining pure iron, refuse to waste materials

Ø   perfect process and records, products are  traceable

Ø   regular training employees, strengthen the quality of  industrial workers

Ø   implement ISO9001:2008 quality standard, 5S management

2.      Strict quality control of powder

Ø  direct reading spectrometric components, ensure qualified

Ø  oxygen content measurement, to ensure standard oxygen content

Ø   tap density measurement, to ensure standard tap density

Ø  batch testing, to ensure standard size of 

Process for Powder metallurgy

Materials and process for powder metallurgy: the formula includes graphite, copper, zinc stearate and iron uniformly mixed iron-based powder; wherein the iron-based powder is also added phosphorus ferroalloys and sulfuric acid manganese; the iron-based powder measured by weight of units, graphite powder is 0.4 to 1.5%, copper powder of 1 to 3%, manganese from 1 to 2.5%, phosphorus alloy 1 % to 2.5%, zinc stearate 0.5 to 1%, iron 70% -98%.

The process include:

(1) mixing

(2) pressing;

(3) sintering;

(4) oil immersion;

(5) fihishing;

(6) rough finish;

(7) Finish machining;

(8) anti-rust treatment.

Meanwhile, the generation of new technology has advantages like increasing product performance and strength, reducing production costs, improving production efficiency, high resistance to wear, shortening sintering time, stable quality.