Hot forging is also called hot die forging by hot forging manufacturers. During the hot die forging process, the deformed metal flows violently and the forging contacts with the die for a long time.
Besides professional cold forging process, cold forging materials, Walkson also provides types of hot forging. Therefore, the mold materials by this forging process flow should have high thermal stability, high temperature strength and hardness, impact toughness, heat fatigue resistance and wear resistance, and be easy to process.
AISI 1010, AISI 1018, AISI 1020, AISI 1026, AISI 4130, AISI 4140, AISI 4330, AISI 4340, AISI 8620, AISI 8630, AISI 9310, Nitralloy 135,
Stainless Steel 300 Series
Grade 302, Grade 304, Grade 304-l, Grade 309, Grade 310, Grade 316, Grade 316-L, Grade 317, Grade 321, Grade 330
Stainless Steel 400 Series
Grade 403, Grade 405, Grade 410, Grade 414, Grade 416, Grade 418, Grade 422, Grade 431, Grade 440-A, Grade 440-C
Precipitation Hardening Grades
13-8MO, 15-5 PH, 17-4 PH, 450, 455
Duplex stainless-steel grades:
2205, 2507, F-55
Monel: 400, K 500
Nitrolic: 40, 50, 60
Hot forging temperature of steel: generally speaking, hot forging temperature ranges from 950°C to 1250°C, which are above the recrystallization temperature. Usually, we can experience good formability (i.e. filling the cavity in the case of forging), low forming forces and almost uniform tensile strength of the workpiece.
Table 1 Comparison of cold forging and hot forging | ||
Cold forging | Hot forging | |
Process temperature | Room temperature | 1 000–1 250°C |
Material flow stress | High | Low |
Forging pressure | High | Low |
Annealing before forging | Necessary | Unnecessary |
Material deformability | Low | High |
Shape of forgings | Complex in some cases | Complex |
Dimensional accuracy of forgings | High | Low |
Surface condition of forgings | Fine | Oxidized and decarburized |
Lubricant | Phosphate coating plus metal soap, etc. | Graphite, etc |
The high temperature during the hot forging process causes the material to deform to the highest level and obtain complex 3D geometry. The higher malleability of hot forging components makes them suitable for many configurations. In addition, as a technology, hot forging is more flexible than cold forging because custom parts can be made. The excellent surface quality of hot forging allows for a wide range of finishing jobs such as polishing, coating or painting according to the customer's specific needs.
Hot forging is most commonly used in automotive forging applications. Wrought aluminum alloys are becoming more popular as the demand for lightweight construction grows; magnesium is rarely used. A variety of common automotive forgings are applicable to both passenger cars and commercial vehicles; Aside from steel forgings, high-strength and temperature-resistant special materials such as nickel-based and titanium alloys, as well as lightweight construction materials such as wrought aluminum alloys and magnesium, are used in the aerospace sector. Hot forging is not only used in the automotive and aerospace industries. Furthermore, there are a few other important application fields in which hot forgings can shine: Construction industry, Mechanical engineering, Agriculture, Steel construction, Offshore Industry etc.