Different forging methods have different processes, among which the process of hot die forging is the longest, and the general order is: forging blank blanking;Forging billet heating;Roll forging blank;Forming by die forging;Trimming;Punching;Correction;Intermediate inspection, inspection forgings size and surface defects;Heat treatment of forgings to eliminate forging stress and improve metal cutting performance;Cleaning, mainly removing the surface oxide scale;Correction;Inspection, general forgings to go through the appearance and hardness inspection, important forgings have to go through the chemical composition analysis, mechanical properties, residual stress and other tests and non-destructive inspection.
closed die Forging Process
we will introduce steel forging process under closed die forging technology in detail. Normally, main steps of closed die steel forging processes are die/tool making, billet cutting, billet heating, forging, trimming, heat treatment, shot blasting, machining, surface treatment, inspection and package.
Step 1. Die design & making
Dies making is the unnecessary step for close die steel forging parts. Once a new order is placed, our engineer will design dies according to steel forging drawing from customers. Unlike casting,steel forging dies will include forging dies, trimming dies and flatten dies, that is why forging dies are much expensive than casting molds.
Step 2. Billet cutting & heating
In our forging company, we will keep some common steel material specifications in stock for continious production. After dies are completed, steel billets will be taken from our material warehouse, then cut into required length and heated by medium frequency furnace before forging.
Step 3. Closed Die Forging
After heating billets, heated steel bars will be placed under upper and lower dies, and then pressed into desire shape, but redundant material will shown around the product, which is named as flash.
Step 4. Trimming
Now forging blanks with flash are obtained, to remove the flash, the forged steel blanks will be put under trimming dies and pressed again. In this step, a whole forging blank is finished.
Step 5. Heat Treatment
In order to improve the strength and mechanical properties of forged products, eliminate the internal stress caused by forging and improve the internal structure of forged products, It is necessary to heat the forgings after they are forged, common heat treatment methods for steel forgings are normalizing, quenching, annealing, tempering & hardening, solution treatment,ect. Of course,heat treatment is only operated when it is required.
Step 6. Shot Blasting
In order to remove the oxide scale caused by high temperature oxidation in the forging process, as well as some small burrs in the forging process, to achieve better surface finish, the steel forgings will be shot blasted.After peening treatment, the product appearance is more clear and smooth.
Step 7. Machining
Many forgings are used in precision machinery and some key assembly positions, which require the size of some workpieces to have ultra-high precision. At this time, it is necessary to cooperate with machining equipment to process the forgings and meet the requirements of product assembly and use.
Step 8. Surface Treatment
If there is no special surface treatment requirement, water/oil anti-rust painting is enough before package. Sometimes special surface treatments are also required according to the application of steel forgings, likeZinc plating, electrophoresis, blackening oxidation, electrostatic spraying , ect.
Step 9. Inspection
Inspection is also an important step. We can divide inspection process into external inspection and internal inspection. External inspection includes: dimention testing,visual defects inspection. And internal inspection refers to internal properties inspection.
Step 10. Package & delivery
Forgings for export are packed in plastic bags in strong fumigation-free wooden cases to protect them from damage during long transit.In addition, we can also customize packaging according to the special requirements of customers.
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