ForgingsTechnical Information

Forging Tech Info

Step 1) Slug Cutting — The raw material size is determined by the Technical Staff and slugs are cut to length.

Step 2) Heat — There are two methods of heating slugs. Induction heating, which uses electricity through a coil that is sized very closely to the diameter of the slug being heated, and gas heating where parts are placed on a belt and fed through a furnace at a speed allowing the slugs absorb heat. In both cases the temperature of the material prior to forge is verified by an optical pyrometer which ensures your part is heated properly. (View Slug Heating video to the right.)

Step 3) Forge — A heated slug is placed onto the lower die and the press is actuated. The die halves close together to force material into the top and bottom die. The forging is then ejected from the tooling using ejector pins which push against the flash outside of the die cavity and eject the part. (View Forge video to the right.)

Step 4) Trimming — Excess material is clipped off of the forging in a trim press. A punch will force the part through a die with a sharp edge around the entire profile of the part. Clippings are returned for recycling while the part is transferred to the finishing step. (View Trimming video to the right.)

Step 5) Finishing — The different surface finishes available are blasted finish, vibratory finish, and in the case of aluminum forging, an etched finish to remove oxides from the surface.

Blasted Finish

Blasted Finish

The most environmentally friendly method is a blasted finish. This method utilizes chips recycled from the sawing operation. Chips are then blasted onto the surface of the forging. This process removes any residue from the forging process.
Etched Finish

Vibratory Finish

Parts are placed into a machine with stainless shot and vibrated to remove residue. Parts are shiny in appearance.

Vibratory Finish

Etched Finish

Aluminum forged parts can be etched which will remove oxides from the surface. This creates a bright silver appearance.

Forging Compared to Other Processes

Vs. Castings

  • A casting cannot compare to a forging in strength. By working the material twice, through extrusion of the bar stock and hot working at forge. A forging has superior properties than that of a casting.
  • Because the forging process is very repeatable, costs can be improved compared to a cast part. The forge process redefines grain with heat and pressure. Castings contain porosity which may cause defects not discovered until the part is machined, costing valuable time and money.
  • Tooling costs for some casting processes can be prohibitive. This is especially true for medium and low volume applications. In comparison, forging tools require relatively low capital.
  • During the machining operation it is very important to maintain dimensional control. Fixturing a forged part is very consistent due to the stable condition of the material and less process variability of the forging process. Reduced distortion of a forging during heat treatment is also an improvement because of material and process stability.

Vs. Machined Bar or Plate

  • Forged configurations can reduce machining time, generate less scrap and lower assembly costs. Material is used where necessary and removed from areas where it is not required reducing raw material and excess machining costs. In some cases features can be incorporated into a forged design that will eliminate an assembled component and possible leak path and reduce secondary machining.
  • Bar stock and plate have grain structures that run in one direction. A forging redefines the grain structure so that strength is imparted into all areas of the part. This improves the metallurgical properties of your design adding strength where bar stock cannot.

Alloy Specifications


Current Material Forged

Alloy Description Comment
Brass and Bronze*
2745 No Lead Plumbing Brass Complies with AB-1953.


DZR No Lead Plumbing Brass

DZR Brass

Low Lead Forging Brass
For lead free compliance and dezincification resistance

For dezincification resistance

Used for Low Lead applications.
3770 Forging Brass General forging use.
4850 Naval Brass High Leaded Marine applications.
6420 Aliminum Silicon Bronze High strength and corrosion resistant.
6731 Dynalloy Bronze Leaded Heat treatable bearing bronze for wear application.
6735 Dynalloy Swash Plate Used for automotive market.
6741 Dynalloy Bronze Non heat treatable bearing bronze for wear application.
2014 Aluminum and Copper Excellent mechanical properties. Heat treatable.
3003 Aluminum and Magnesium Moderate Strength. Non heat treatable. Brazeable applications.
4032 Aluminum and Silicon High wearing properties.
6020 Aluminum and Tin Suitable replacement for leaded aluminum alloys.
v62 SN Aluminum and Tin Suitable replacement for leaded aluminum alloys.
6061 Aluminum with Silicon and Magnesium Heat treatable and medium strength. Very versatile with many applications.
6063 Aluminum with Silicon and Magnesium Heat treatable and medium strength. Brazeable applications.
6082 Aluminum with Silicon and Magnesium Heat treatable and medium strength. Very versatile with many applications.
7075 Aluminum and Zinc Heat treatable and very high strength. Applications for highly stressed parts.
A390 Aluminum with Silicon and Copper Heat treatable. For highest strength applications.

* Other materials available. Please consult Mueller with any requests.

Tech Tables


Forging Criteria

  Brass Aluminum
Draft Angles 2-3° 3-5°
Radii 0.06 0.13
Machining Allowance .030 Min. .030 Min
Flash Thickness 0.04 0.06
Flash Extension .030 Max. .030 Max

Forging Tolerances

  Brass Aluminum
Linear Dimensions ±.015 0.02
Angular Dimensions ±1° ±1°
Radial Dimensions ±.015 ±.020
Concentricity .020 TIR .030 TIR
Mismatch .020 Max .020 Max
Flash Thickness 0.04 0.06
Flash Extension .030 Max. .030 Max.
Flatness .005/inch .005/inch
Surface Finish 63-250 rms 63-250 rms

*All design criteria subject to review of actual geometry. Dimensions are in inches.

Simulation Examples

Mueller Forging Company has Design Simulation capability.

This advanced technology allows our engineers to assist you in analyzing metal flow and tool stresses to create the best component for both the user and manufacturer.

  • Metal flow analysis prior to tool build ensures robust design and quality.
  • Tool stress analysis addresses any manufacturing issues prior to production. The result is an optimized process and smooth new product launch.