Preparation Method Of High Hardness Hammer Head With 4Cr5MoSiV1 Hot Forging Die Steel.

- Jan 10, 2018 -

The steps are as follows :1) matrix forging: the matrix material is 4Cr5MoSiV1 hot-forging steel, its chemical composition :C 0.32%~0.42%, Si0.80%~1.20%, Mn is less than 0.40%, Cr 4.5%~5.5%, Mo 1.0%~1.5%, V 0.8%~1.0%, the rest is Fe;

Hot-work die steel forging process: forging temperature is 750 ~ 800 , the forging ratio 2.5 ~ 2.5;

Forgings anneal process is: 860 ~ 890 , 1 ~ 4 h insulation, furnace cooling to 540 , air cooling;

2) substrate heat treatment: 4 cr5mosiv1 steel forging heat treatment process: 1000 ~ 1050 oil quenching, 500 ~ 600 tempering;

3) surface treatment of the matrix: polishing and blasting of the working face of the matrix;

The treatment process is 40~80 white sand, HRC 70~90, processing time 1~2 hours;

4) laser cladding of the matrix working face;

(a.) cladding materials selection: work surface laser cladding materials for 146 # cobalt base alloy powder materials, components according to the quality percentage content is: C: 0.7% ~ 1.5%, Si: 0.41% ~ 0.41%, the Fe: 2.16% ~ 2.85%, Ni: 2.27% ~ 2.5% and Cr: 29.5% ~ 32.4%, Mo: 0.12% ~ 0.26%, W: 8.7% ~ 17.8% and the rest for Co.

(b.) powder drying and substrate preheating: put 146 # cobalt base alloy powder materials in the vacuum drying oven, under the condition of 100 ~ 150 heat preservation 1.5 ~ 2 h, natural cooling.

At the same time, the substrate 4 cr5mosiv1 hot-work die steel using intelligent temperature control heating equipment, in 150 ~ 200 preheat 1.5 ~ 2.5 h;

(c.) laser cladding: the thickness of each layer is 3~5mm;

The process parameters are: laser power 3KW, scanning speed of 4.5~5.5mm/min, spot diameter of 4mm, lap rate of 30%, powder delivery of 6~8g/min, cladding layer of 3~5 layers;

5) mechanical processing, performance testing, warehousing.

Existing technology

The basic principle of radial forging was proposed by the Austrian scientist Dr. B.r. ralowetz in 1946.

By the mid-1970s, the radial forging machine with 6.5MN to 25MN was successively developed and applied to high alloy steel and other alloys (such as tungsten alloy) and forged ingots.

Radial forging is a forming method of the forging force which can apply several weeks to uniform distribution of axial parts on the same plane.

Hammer closed-die forging machine is one of the important parts of forging machine, it depends on the substrate connecting with each other into 90 ° on the four pillars of hammer rod.

The hammer rod is connected to the crankshaft connecting rod mechanism, and the motion is synchronized with the crankshaft, and the radial strike of the hammer head is realized.

DA65-100 type radial forging machine due to the forging of high precision, simple and flexible operation, widely used in the alloy structural steel, high strength alloy steel, titanium alloy, and difficult to deformation of the alloy pressure processing field, to improve the material performance and improve the internal structure has played an important role.

At present, the preparation method of the hammer head of the da65-100 precision forging machine is: firstly, 3Cr2W8V is selected as the base material, and the high strength, hardness and better comprehensive mechanical properties are obtained after heat treatment.

Then, the surface of the substrate material is surfacing with high temperature alloy, which is formed by machining and working surface.

But because the hammer of the surface of the work over a long period of time of hot metal in contact with high temperature conditions, and under a lot of impact load and deformation of metal flow in the process of blow of friction, easy to deformation, cracks, and fracture scrap.

It is difficult to meet the production requirement of high performance alloy with hammer head.

The bad service conditions have high technical requirements for the hammer head, such as red hardness at high temperature, anti-impact fatigue crack, anti-fatigue crack, crack resistance, creep resistance and so on.

Therefore, the development of new long-life hammer head has become a main task.