The ball is the opening and closing part of the ball valve, also known as the ball core and ball. The ball rotates around the center line of the valve body to open and close the ball valve. The ball valve can cut off, adjust, distribute and change the flow direction of the medium in the pipeline. Ball valve has many advantages and is a new type of valve widely used in recent years. Ball valves with different functions often have different balls.

1、 Comparison of ball forming methods

(1) Ball valve ball casting method

Casting method is a traditional processing method. It requires a complete set of smelting, pouring and other equipment, as well as a large plant and more workers. It requires large investment, many processes, complex production processes and pollutes the environment. The technical level of workers in each process directly affects the quality of products. The problem of leakage of valve ball pores cannot be completely solved, while the blank processing allowance is large and the waste is large, It is often found in the process of processing that the casting defects cause it to be scrapped, so that the product cost increases and the quantity cannot be guaranteed.

(2) Ball forging method

Forging method is another method adopted by many domestic valve enterprises at present. It has two processing methods: one is to use round steel to cut, heat and forge into spherical solid blanks, and then carry out mechanical processing. The second is to press the circular stainless steel plate on a large press to obtain a hollow hemispherical blank, and then weld the valve ball blank for machining. This method has a high material utilization rate, but requires a high-power press, heating furnace and argon arc welding equipment.

① Free forging of ball valve

Free forging refers to a processing method in which the metal blank is heated and placed between the grinding irons (upper and lower) of the forging equipment to apply impact force or pressure, so that the blank directly produces plastic deformation and obtains the forgings to be produced. Classification: manual free forging, hammer free forging, hydraulic press free forging advantages: strong applicability, large flexibility, short cycle, the only method for large forgings disadvantages: low precision, large machining allowance, low efficiency, and high labor intensity

② Die forging of ball valve

The formal term of die forging is called model forging. After the billet is heated, it is put into the forging die fixed on the die forging equipment for forging and finally formed.

Die forging equipment: in industrial production, hammer die forging is mostly used. Hot die forging press is the most popular die forging press with steam air hammer and tonnage of 5kn ~ 300KN (0.5 ~ 30t).

③ Forging ratio of ball valve

Forging ratio: refers to the ratio of the cross-sectional area of the blank (metal) before and after forging. Different processes have different calculation methods and methods. When drawing, the forging ratio is y = F0 / F1 or y = L1 / l0fo, Lo is the cross-sectional area and length of the ingot or billet before drawing; F1, Lo is the cross-sectional length and area of steel ingot (Billet) after drawing.

The forging ratio during roughening, also known as the roughening ratio or compression ratio, is y = F1 / F0 or y = H0 / h1f0, Ho is the cross-sectional area and height of the ingot or billet before roughening, and F1, H1 is the cross-sectional area and height of the ingot or billet after roughening.

④ Forging temperature of ball valve

A. initial forging temperature: the initial forging temperature can be considered as the maximum allowable temperature of steel or alloy in the furnace.

b. Final forging temperature: valve fittings need to have strong plasticity before the end of forging, and obtain recrystallized structure after forging.

(3) CNC ball grinder on ball valve

Methods and steps for starting automatic operation:

1: Press the (open program) key;

2: Enter the program number, for example, enter the name of the rough grinding program (p-0-0-0-1);

3: Press enter

4: Press the position key (POS);

5: Press the auto key (F4);

6: Press the green key (cycle start) to start the automatic rough grinding of the machine tool;

7: Press the yellow key when the grinding of the surface roughness of the ball is completed (cycle pause);

8: Press the blue key (cycle cancel);

9: Press the (open program) key;

9: Enter the program number, and then type the name of the fine grinding program (p-0-0-0-2)

10: Press enter

11: Press the position key (POS);

12: Press the auto key (F4);