Concrete Pump Elbow Correct cleaning method
Correct Clearing Method of Concrete Pump Elbow
Concrete pump elbow has a certain corrosion resistance (oxidizing acid, organic acid, cavitation), heat and wear resistance. Usually used for power plants, chemical, oil and other equipment materials. Concrete pump elbow weldability is poor, should pay attention to welding process, heat treatment conditions and the selection of suitable welding electrodes. Concrete pump elbow is mainly stainless steel, stainless steel contains chemical composition will keep the concrete pump elbow surface for a long time not to be corroded, no rust, in the cleanup we also need to pay attention to the following two aspects:
First, according to the requirements of the workpiece and the surface condition using alkali washing, water-soluble cleaning agent, chlorine solvent blasting, shot peening and other methods to clean up;
Second, the concrete pump elbow to clean up, generally do not use pickling method to clean up.
Correctly clean the concrete pump elbow, can improve the safety performance of its use, to extend its use cycle.
The electrode should be kept dry when used. The titanium calcium type should be dried at 150 ℃ for 1 hour. The low hydrogen type should be dried at 200-250 ℃ for 1 hour (it can not be dried repeatedly, otherwise the skin is easy to peel and peel) Sticky oil and other dirt, so as not to cause the weld to increase the carbon content and affect the quality of the weldment. Elbow welding, by repeated heating precipitation of carbides, reducing corrosion resistance and mechanical properties. After welding hardening is large, prone to crack. If the same type of welding electrodes, must be more than 300 ℃ preheating and 700 ℃ after the slow cooling treatment. If the weldment can not be post-weld heat treatment, you should use chrome-nickel stainless steel electrode.
In order to improve the corrosion resistance and weldability of concrete pump elbow, it is necessary to increase the amount of Ti, Nb, Mo and so on. The welding quality is better. When using the same type of chromium stainless steel electrode, it should be preheated above 200 ℃ 800 ℃ after the tempering treatment. If the weldment can not be heat treatment, you should use chrome nickel stainless steel electrode.
A. Hot push forming
The heat-pushing elbow forming process uses a special elbow pushing machine, a core mold and a heating device so that the blank placed on the mold is moved forward with the pushing of the push machine and is heated, expanded and bent during the movement the process of. The deformation of the thermocouple is characterized by the fact that the diameter of the tube is determined according to the law of the volume before and after the plastic deformation of the metal material. The diameter of the tube is less than the diameter of the elbow, and the deformation of the blank is controlled by the core mold, Of the metal flow, to compensate for the expansion of the other parts of the thinning, resulting in uniform wall thickness of the elbow. The hot bend forming process has the advantages of beautiful appearance, uniform wall thickness and continuous operation, suitable for mass production, and thus become the main forming method of carbon steel and alloy steel elbow, and also used in some specifications of concrete pump bending The shape of the head. The heating process of the forming process is medium frequency or high frequency induction heating (heating ring can be multi-lap or single lap), flame heating and reverberatory furnace heating, using what kind of heating method as the molding product requirements and energy decisions.