Technical Measures for Forging Special Alloys

Special alloy forging is much more difficult than ordinary carbon steel and low alloy structural steel. To produce special alloy forgings that meet the requirements of geometric dimensions and metallurgical quality, corresponding targeted technical measures must be taken according to different characteristics. These measures mainly include process measures, forging and mold design measures, quality control measures, testing of forging performance (based on the selection of thermodynamic parameters), and simulation of the forging process.

The process measures that need to be taken among the above measures are described as follows:

Reasonably selecting the temperature, heating speed, and insulation time for the raw material entering the furnace

For special alloys with low thermal conductivity (especially large-sized billets), they should be preheated and held for a period of time at a low speed with the furnace or at 800 ° C~850 ° C, instead of being directly heated in the furnace at the initial forging temperature, and then heated to the initial forging temperature or transferred to a high-temperature furnace at the initial forging temperature for heating; The insulation time at the initial forging temperature depends on the alloy and is generally several times longer than that of alloy structural steel.

Other blanks of aluminum, magnesium, copper, and their alloys with higher thermal conductivity than steel can be directly fed into a high-temperature furnace, with faster heating speed and appropriately shorter insulation time.

02 Proper selection of deformation degree

In response to the characteristics of high alloying degree of special alloys, severe macroscopic segregation of ingots and forgings, low plasticity, and wide critical deformation range, each heat must be strictly controlled during the forging process. Even the degree of deformation of each stroke of the equipment; Excessive deformation may lead to forging cracks, while excessive deformation may fall into the critical deformation zone, leading to local grain growth and uneven microstructure.

03 Strictly control the final forging temperature

In response to the high recrystallization temperature and obvious cold work hardening tendency of special alloys, it is necessary to increase or significantly increase the final forging temperature. The final forging temperature of some alloys can even reach 1080 ° C, which is about 300 ° C higher than that of ordinary carbon steel and low alloy structural steel.

04 Reasonable selection of working speed for forging equipment

For some special alloys that are sensitive to strain rate and have slow recrystallization speed, hydraulic press, mechanical press and Screw press with lower loading speed should be selected as far as possible for forging; For high-speed steel with severe network carbides, in order to completely break the network carbides, a forging hammer with high working speed and strong impact force should be selected for forging.

05 Reasonable selection of forging equipment

For certain special alloys with high deformation resistance, slow recrystallization rate, and high final forging temperature, compared with carbon steel and low alloy structural steel forgings of the same size, forging equipment with energy or load greater than 3-5 times or more needs to be selected.

In the same situation, molybdenum, magnesium, steel and their alloys with low deformation resistance require the selection of smaller equipment.

06 Protect the blank

In response to the characteristics of easy formation of alloy element depletion and embrittlement layers or absorption of harmful gases on the surface of special alloys during the heating process, heating should be carried out in a protective atmosphere or protective coatings should be used to protect the blank under possible conditions, such as coating the blank with glass protective lubricant.

07 Double lubrication of blanks and molds

In response to the characteristics of high deformation resistance, high equipment energy (load) required, and narrow forging temperature range of special alloys, in addition to conventional mold lubrication, protective lubrication should also be applied to the blank to minimize friction and temperature drop, in order to reduce the required equipment tonnage. It is recommended to use glass protective lubricant to protect and lubricate the blank during high-temperature alloy, titanium alloy, and stainless steel forging.

08 Try to choose the forging process under compressive stress as much as possible

In response to the characteristics of high alloying degree and low plasticity of special alloys, it is recommended to choose the forging process under compressive stress conditions such as extrusion, closed die forging, and closed upsetting and extrusion on flat forging machines as much as possible.

09 "Strike while the iron is hot"

In response to the characteristics of high final forging temperature and narrow forging temperature range of special alloys, it is required that the forging worker should be proficient in operation and sensitive in response. Every step from billet discharge, transmission to forging should be rapid and accurate, and efforts should be made to shorten the forging time as much as possible to achieve the goal of "striking while the iron is hot".

Strictly implement the preheating system for tools and molds

In response to the characteristics of high final forging temperature, narrow forging temperature range, and low thermal conductivity of special alloys that are sensitive to mold quenching, all fixture molds in contact with forgings must be preheated strictly according to regulations.

Some Little Knowledge about Hot Die Forging Press

The generation, harm, reduction, and treatment of oxidation during forging heating process

Some Little Knowledge about Hot Die Forging Press

The generation, harm, reduction, and treatment of oxidation during forging heating process

In July 2019, Minghui Company signed contracts with Korean clients for J58A-4000T and J58A-630T

2020-12-04

Successful installation and commissioning of J58A-4000T electric Screw press exported to South Korea

2020-12-04

Qingdao Minghui Metal Forming Machinery Co.,Ltd specializes in the production of J58A series electric CNC Screw press and FP/MP series hot die forging presses. The company has a strong technical force. Since its inception, the company has been adhering to the business philosophy of "responsibility, integrity and pragmatism", and has been forging ahead in business activities.

Qingdao Minghui Metal Forming Machinery Co.,Ltd

Address: Taiwan Industrial Park, Jiaozhou City, Qingdao, Shandong
E-mail: sales@qdmhjx.com

Contacts: Mr Wang
Phone: +86 18663977787

Fax: 86-0532-83281398

Address: Taiwan Industrial Park, Jiaozhou City, Qingdao, Shandong
E-mail: sales@qdmhjx.com

Contacts: Mr Wang
Phone: +86 18663977787

Fax: 86-0532-83281398