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Production process and basic working procedure of stainless steel flange

The production process of stainless steel flange mainly includes forging, casting, cutting and rolling.


(1) Cast and forged flanges
The results show that the shape and size of the blank are accurate, the machining quantity is small and the cost is low, but there are casting defects (air holes, cracks and inclusions); the streamline of the internal structure of the casting is poor (if it is a cutting part, the streamline is worse);
Forging flange generally contains less carbon than casting flange, is not easy to rust, has good streamline, compact structure and better mechanical properties than casting flange;
Improper forging process will also lead to large or uneven grains, hardening cracks, and the forging cost is higher than that of casting flange.
Forging can bear higher shear force and tensile force than casting.
The advantage of casting is that it can produce complex shape and low cost;
The advantages of forgings are that the internal structure is uniform, and there are no harmful defects such as pores and inclusions in the castings;
From the production process difference between casting flange and forging flange, such as centrifugal flange is a kind of casting flange.
Centrifugal flange is a kind of casting method to produce flange. Compared with ordinary sand mold casting, this kind of casting has much finer structure, much higher quality, and is not easy to have problems such as loose structure, air hole and trachoma.
First of all, we need to know how the centrifugal flange is produced and how the centrifugal casting process is used to make the flat welding flange
① The selected raw materials are melted in the medium frequency electric furnace to make the molten steel temperature reach 1600-1700 ℃;
② Preheat the metal mould to 800-900 ℃ and keep constant temperature;
③ Start the centrifuge and inject the molten steel in step 1 into the metal mold after preheating in step 2;
④ The casting is naturally cooled to 800-900 ℃ for 1-10 minutes;
⑤ Take out the casting and cool it to room temperature, and demould it with water.
Let's learn more about the production process of forged flange
The forging process is generally composed of the following processes: billet blanking, heating, forming and cooling after forging. The forging process includes free forging, die forging and membrane forging. During production, different forging methods should be selected according to the forging quality and production batch.
Free forging has low productivity and large machining allowance, but its tools are simple and versatile, so it is widely used to forge single piece and small batch forgings with simple shape. The free forging equipment includes air hammer, steam air hammer and hydraulic press, which are suitable for the production of small, medium and large forgings respectively. Die forging has the advantages of high productivity, simple operation, easy mechanization and automation. Die forgings have high dimensional accuracy, small machining allowance and more reasonable distribution of fiber structure, which can further improve the service life of parts.
Basic process of free forging: in free forging, the shape of forgings is gradually forged by some basic deformation processes. The basic processes of free forging include upsetting, drawing, punching, bending and cutting.
1. Upsetting upsetting is the operation process of forging the original billet along the axial direction to reduce its height and increase its cross section. This process is often used to forge gear blanks and other disk forgings. Upsetting can be divided into full upsetting and local upsetting.
2. Lengthening and lengthening is a forging process that increases the length of the blank and reduces the cross section. It is usually used to produce shaft blanks, such as lathe spindle, connecting rod, etc.
3. Punching forging process of punching through or through holes on the blank with a punch.
4. The forging process of bending the blank to a certain angle or shape.
5. The forging process in which one part of the blank rotates at a certain angle relative to the other part by torsion. 6. Forging process of cutting and dividing the blank or cutting off the head.
(2) Die forging
Die forging is called model forging. The heated blank is forged in the forging die fixed on the die forging equipment.
1. The basic process of die forging: blanking, heating, pre forging, final forging, punching and peeling, trimming, quenching and tempering, shot peening. Common processes include upsetting, drawing, bending, punching and forming.
2. Common die forging equipment common die forging equipment include die forging hammer, hot die forging press, flat forging press and friction press, etc. Generally speaking, forged flange quality is better, generally through die forging production, crystal structure fine, high strength, of course, the price is more expensive. Both cast flange and forged flange belong to the common manufacturing method of flange. It depends on the strength requirements of the parts to be used. If the requirements are not high, turning flange can also be selected.
(3) Cutting flange
The inner and outer diameter and thickness of the flange are directly cut out on the middle plate, and then the bolt hole and water line are processed. The flange produced in this way is called cutting flange. The large diameter of this kind of flange is limited by the width of the medium plate.
(4) Rolled flange
It's called the multi roll cutting process, which is used in the production of large flange. After successful rolling, welding, then flattening, and then processing the waterline and bolt hole.

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