I just welded together two pump housings for a friend after they got caught in an early freeze last year.I found a rod made by an outfit called muggy weld. (See link below) When I used this rod I heated the part to about 100°-150° to sweat the moisture out of the metal. Then I ground a V in the crack to about ½ to ¾ the thickness of the piece. After that I welded about ¾&#; at a time working from both ends of the break. I found that if I let the piece get too hot lots of porosity would ensue. The heat must be as low as you can get it and still be able to hold an arc.So far the pieces are holding up. One pump housing was especially big with a 4&#; flange and a 15 horse three phase electric motor off the end of it. He is irrigating a cherry orchard with it.I have both brazed and used high nickel rod on cast parts with much success. The muggy stuff is easier. So far it works. I like easy.Jon
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A pump is a pumping machine that uses the centrifugal motion of water. It is composed of pump casing, impeller, pump shaft, motor and so on. The purpose of the pump casing vent is to expel air so that the pump can be filled with water before it is first started. As a pump parts casting manufacturer, we have rich experience in pump casing casting. The following is a detailed introduction to the common pump casing materials
There are several factors to consider when selecting a pump casing material. Including: material strength, corrosion resistance, abrasive wear resistance, casting and machining performance, welding repair performance, cost. The following are common materials in casting
1. Bronze
Lead bronze is often used in small low-pressure pumps, and the lead helps to seal the pump body. Bronze material is also used for the pump body in many water pump applications. Tin bronze is used as the body material for larger centrifugal pumps. The mechanical properties and corrosion resistance of Nickel Aluminum Bronze are very good. But it's expensive and not competitive.
2. Cast steel
Common cast steels include martensitic stainless steel, austenitic stainless steel, duplex stainless steel, etc. For corrosive and harmful petroleum products, or when the outlet pressure of the multi-stage pump reaches 138Mpa, the specified cast steel or cast stainless steel must be used.
Martensitic stainless steel has good mechanical properties and is suitable for high-pressure working conditions. It is commonly used in boiler feed pumps and many hydrocarbon applications. But its corrosion resistance is not as good as other types of stainless steel.
Austenitic stainless steels are corrosion resistant and have relatively easy field weld repairs. Therefore, in chemical applications and other corrosive environments, austenitic stainless steel (CF-8M, CF-3M, etc.) is often used as the pump casing material.
High-pressure shallow sea water injection pumps have higher requirements on corrosion resistance and mechanical properties. The pump casing used in this environment is made of duplex stainless steel (50% ferrite + 50% austenite).
As the strength of cast steel becomes higher, usually when the pressure is greater than 16Mpa, the pressure-bearing parts are mostly cast steel. The national standard code is ZG, and the most commonly used grade is ZG230-450. Japan and the United States usually use CS to indicate cast steel.
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3. Cast iron
Gray cast iron is the most commonly used cast iron, and the national standard code is HT. Generally, the pump body, impeller, pump cover, suspension, etc. of the clean water pump are made of this material, and usually use three grades: HT150, HT200, HT250. HT150 is mostly used for non-main parts such as base and back plate, HT200 is mostly used for pump body, pump cover, suspension, etc., and HT250 is mostly used for impeller, mouth ring and shaft sleeve.
Gray cast iron is the better material for pump casings for most liquid transfer applications. For single stage pumps, gray cast iron is usually strong enough to withstand the pressures generated. In the range of medium pressure and temperature, nodular cast iron is widely used. In applications where gray and nodular cast iron cannot achieve sufficient corrosion resistance, corrosion resistant high nickel cast iron is often used as the pump body material. In recent years, a new corrosion-resistant high-nickel cast iron material (named D2W) with good welding performance has been developed, which contains a small amount of niobium to improve its welding performance. Typical austenitic cast irons contain 15% to 20% nickel and are widely used in salt water.
Ductile iron is a kind of cast iron with better comprehensive performance, and the national standard code is QT. Because its mechanical properties are close to steel, and its casting performance and processing performance are better than steel, it is usually used as a substitute for cast steel.
4. Stainless steel
The most widely used stainless steel is austenitic stainless steel, such as 0Crl8Ni9, 1Crl8Nij9Ti, 0Crl8Ni2Mo2IIIi, etc. Except for a few media such as hydrochloric acid and dilute sulfuric acid, austenitic stainless steel is an excellent corrosion-resistant material and is the most commonly used corrosion-resistant material for chemical pumps. Japan and the United States usually use SS304, SS316, SS316L to represent austenitic stainless steel. 2Cr3, 3Cr13 and other martensitic stainless steels have better mechanical properties than austenitic stainless steels. They are commonly used as materials for pump shafts and bushings. The code corresponding to Japan and the United States is SS420. In addition, high-alloy stainless steel (alloy 20) and duplex stainless steel are ideal corrosion-resistant materials.
5. Carbon structural steel
It is usually divided into ordinary carbon structural steel and high-quality carbon structural steel. The most representative ordinary carbon steel is Q235, which is mostly used in various steel plates and section steels; the most representative high-quality carbon steel is No. 45 steel, which is widely used as pump shaft material without corrosion.
6. Alloy steel
The most representative alloy steel is 40Cr, which is usually used as a material for high-strength pump shafts.
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