Stainless Steel Casting Machining

Specifications

Stainless Steel Casting Machining  
Material: Stainless Steel AISI304, AISI316 And Others 

1)    Investment Casting

Investment Casting (also called lost-wax casting) as its name implies, utilizes the free shape forming of wax followed by 5 layers of ceramic shell made of silicon mallet sand. Each layer of ceramic shell applied is of a different grade; they must cover thoroughly and be dry before the next layer is added on the top of the previous layer. When all five layers of ceramic are formedsecurely, the wax inside the ceramic is removed using steam, heat and pressure. Molten stainless steel is then poured into the ceramic moldings for the product to take shape. It can produce complicated shapes that would be difficult or impossible with other processes.

2)    Hot Forging

Forging is often classified according to the temperature at which it is performed: "cold", "warm", or "hot" forging. Stainless Steel are almost always Forging utilizes mainly round bar sections, heated to 1020°C forging temperature. At this temperature, the stainless is soft enough for press forming, but does not melt. Using high compression and dies, the required form of the product can be produced. Forging can produce a piece that is stronger than an equivalent cast or machined part. The molecules are highly compacted to form very high-strength components. The disadvantages of Forging components are the limited forms and shapes as well as high molding costs.

3)    Stamping

Stamping includes a variety of sheet-metal forming manufacturing processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining. This could be a single stage operation where every stroke of the press produces the desired form on the sheet metal part, or could occur through a series of stages. A variety of after-forming processes, including welding and assembly, can be added to Press forming products to achieve the desired end product. The process is usually carried out on sheet metal. This form of manufacturing can be very economical. However the disadvantages are the limited thickness as well as high molding cost.

   4) Machining 

Conventional machining is a form of subtractive  manufacturing, in which a collection of material working processes utilizing power-driven machine tools, such as saws, lathes, milling machines, and drill presses, are used with a sharp cutting tool to physically remove material to achieve a desired geometry. The processes include: CNC Machining, General Engineering, Turning, Drilling, Polishing, Knurling, Tapping, Threading, Burnishing, Milling, etc. By taking a solid block of Stainless steel, or a round bar section. Just about any shape or form can be achieved by the combination of Turning and Milling. Never-the-less these are not ideal manufacturing procedures and depending on the formrequired, it may take several hours just to achieve one single item. However, in some casesand depending on the shape of the required product, machining may be the most economicaland fastest production method. Also, due to the fact that machining is always done from awrought-worked block of stainless steel or a solid round bar, the strength on the final productmay be as high as that of forged products.

To overcome the constraints of one single forming method, a production design with acombination of production methods is the best solution. Please notify us in advance wheneverpossible when you need assistance in designing your desired product. This will reduce tool costsas well as time in production.

Finish Details:

   1) Threading

Threading can be classified in general as internal threading or external threading.

In internal threading, threads are on the inside of a circular tube and this process is referred to as Tapping. Tapping is usually preceded by drilling to achieve the specified dimensions before the internal threads are tapped.

External threads may be produced by Rolling or Cutting. In rolling, the bar is pre-finishedto specified dimensions, and using compression of two roller dies the thread is pressedinto form. These threads are easy to press and are on average 25% stronger than a Cutthread. However, Roller threads require more expensive equipment and more product. Cut threads are on the other hand produced by a simple turning machine. The cost ofproduction per unit may be high, but it is the most economical method when quantitiesof required pieces are small or very odd-thread specifications are required.

   2) Welding

Welding stainless steel is more critical than normal steel welding. In order to protectcontaminating the exposed surface of heated stainless steel, a protective layer of Argonis applied. Further Fillers may be added to extend the strength of the desired products.The two most common welding processes are TIG and MIG welding. MIG

uses a highertemperature and thus results in a stronger and more expensive weld.

 3) Surface Finish

Surface finish is one of the most critical areas of product design; it will determine howend users perceive the value of the product as well as product resistance to the environmentand tea stain. Deciding on a product’s finished surface is best achieved by considering theenvironment where the item will be used. As a general rule of thumb, the finer the surface,the more the cost of manufacturing as well as better Corrosion resistance.

a.)                 Mirror polished finish is the most expensive of all finishes. It involves several layers of finegrinding and waxing to arrive at a mirror exterior. Due to the fine finish it is least susceptibleto tea stain forming. For this reason marine fittings, which are exposed to sea water,are finished this way.

b.)                 Machine finish is turned (cut) on a Lathe. This results in a very uniform, lined finish andthus has a very mechanical look to it.Matt finish is polished by a satin grade of 800 rollers; it provides a non-reflective surfacesimilar to Machined finish.

c.)                  Sand blasting finish uses a combination of blast elements; most popular are glass beadsto uniformly destroy the surface; light is then reflected from within the spherically dentedsurface created by the blasting. This surface is very popular for interior designers for itsaesthetic affect as well as its finger-print-resistant feature.

d.)                 Electro polished finish uses electricity in a tank of chemicals. Similar to a wet batterysetup, the outer layer of molecules of the stainless steel product is pealed away exposingthe Chromium molecules resulting in a shining and corrosion-resistance finish.

   4) Passivation

Passivation is the process of making a material "passive" in relation to other contaminants. In stainless steel this is achieved by rinsing the items with a dilute solution of nitric acid and peroxide alternating with deionized water. The nitric acid and peroxide oxidizes and dissolves any impurities on the exposed surface of the stainless fitting, and the deionized water rinses away the acid and oxidized impurities. This process adds an extra layer of protection to Stainless steels surfaces.

Once a stainless steel product goes through the above main forming methods, a varietyof finishing details will follow. In this section we will cover the most common methods ofstainless steel finishing processes.

Requesting a quotation is simple: send us a physical sample or electronic drawing in .dwg / pdf file of the product you are after together with the following information:

a.) Quantity

b.) Name of material

c.) Method of manufacturing

d.) Grade or UNS number

e.) Tolerances

f.) Heat treatment

g.) End finish required

h.) Surface conditions

i.) Test report required

j.) Packaging methods

k.) Shipment methods

Should you not have the above information, we will work with you to determine a best value format to suit your needs. The more detailed information we receive in regard to the use of the item will allow us to better suggest production methods to maximize value and reduce production time.