Hot Forging

Metal forming :Hot die forging

At present,Weforging Manufacturing Company has 6 sets of 400T-1000T-1600T-2500T-4000T hot die forging presses,10 sets of 63T-125T-315T-400T-630T-800T-1000T-1250T closed type presses,2 CNC ring forging machines and 4 oil presses. Mainly with hot die forging;25T-40T-63T-200T-630T-800T forging hydraulic press, mainly used for cold extrusion and nut forging.

The forging base has a total of 20,000 square meters, and the cutting machine is used in the whole process.

The production line is heated by infrared temperature-controlled IGBT induction heating furnace, with an annual capacity of 30,000 tons.

Current machining equipment in Weforging:

The main types of hot forgings are shaft, gear, cylinder, disk and special-shaped. Involved in mining machinery parts, Marine forgings, energy forgings, agricultural machinery, forestry machinery, engineering machinery, engines and other mechanical equipment construction field, weight in 0.01-1000kg. The precision reaches the international advanced standard of hot precision forging.

Laboratory:

Mechanical properties Lab three

Mitoyo three coordinate measuring room

Gear measuring room

Why hot forging

Forging is a kind of metal forming technology, which is widely used in gear and other mechanical fields requiring high safety performance.

Hot die forging is a way of forging, usually refers to the rod by heating to a higher temperature than the recrystallization of the material,and in a certain mold cavity, through the pressure forging equipment, so that the metal flow in the mold cavity, and plastic forming into the shape and size required for forging, and finally cutting, punching and correction.

Hot die forging and free forging

Hot die forging:

Suitable for certain shape, high precision, mass production;
The mold cost is high, but the single cost is low and efficient;
Temperature controllable, relatively stable quality, suitable for mass production;

Free forging:

Suitable for forging of large/heavy parts (Marine drive shaft).
Simple mold cost is low, but the material waste is large, and is not conducive to subsequent machining.
Suitable for small batch customization or trial production stage verification;

Forging forming and testing process flow:

(1) Cutting

Blanking: Cutting raw materials (bars, ingots, etc.) into billets of the desired size.

(2) Heating and pre-forging (preforming)

Heating: the billet is heated above the recrystallization temperature (such as carbon steel is usually 1100~1250 ° C) to improve metal plasticity and reduce deformation resistance.
The initial forming on the free forging or coarse die forging equipment can reduce the metal flow resistance during the final forging and improve the die life.

Common methods: roll forging, upsetting, drawing and so on.

(3) Final forging (die forging forming)

The pre-forged blank is placed in a precision matched upper and lower die and formed under the action of a press or forging hammer.

(4) Trimming and punching

Trimming: Remove the flash around the forging.

Punching: If the forging has internal holes, it needs to be punched.

(5) Heat treatment

Normalizing/annealing: eliminate internal stress and improve tissue uniformity.

Tempering (quenching + tempering) : improve the strength and hardness of forgings.

(6) Finishing and inspection

Correction: removal of deformation (e.g. thermal or cold correction).

(7) Flaw detection and performance testing

Magnetic particle or ultrasonic inspection to detect surface and internal defects
Mechanical properties:
Tensile test: test standard ASTM E8 / GB/T 228.1
Impact test: Test standard ASTM E23 / GB/T 229
Jin Xiang: Analysis of composition and structure
Through the strict implementation of the above testing system, to ensure the reliability, consistency and traceability of hot die forging parts.

Forging (Die Forging) and Casting, formatted as a clear image-ready summary:

In terms of strength, forging (die forging) has a superior advantage due to its aligned grain flow and absence of voids, while casting has relatively lower strength due to the risk of porosity. In terms of precision, forging can reach ±0.1–0.5mm, close to net shape, while casting has moderate precision at ±0.5–2mm, often requiring subsequent machining. In terms of material utilization, forging produces less waste with a yield rate of 80–95%, whereas casting requires additional gating and risers, resulting in a yield rate of only 50–70%. Regarding costs, forging has high tooling costs but is suitable for mass production to spread costs, while casting has lower initial tooling costs. In application scenarios, forging is commonly used for manufacturing critical components such as gears, shafts, and aerospace parts, while casting is suitable for complex-shaped parts like housings and pumps. Additionally, forging may have defects such as folds and cracks, while common defects in casting include porosity, shrinkage, and slag inclusions.