The **15CrMo boiler tube** is manufactured using high-quality carbon structural steel, with specific alloying elements added to enhance its mechanical properties, toughness, and hardenability. Components made from this steel typically require heat treatment processes like normalizing or quenching and tempering. Additionally, surface treatments such as carburizing, nitriding, or high-frequency quenching may be necessary to optimize performance. Based on their chemical composition, heat treatment methods, and intended use, these steels can be categorized into three main types: carburizing, quenching and tempering, and nitriding.
When classifying high-pressure boiler tubes, we encounter various grades. For high-quality carbon structural steels, common grades include 20G, 20MnG, and 25MnG. For alloy structural steels, grades such as 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, and 12Cr3MoVSiTiB are widely used. Certain rust-resistant and heat-resistant steels like 1Cr18Ni9 and 1Cr18Ni11Nb are also popular choices for boiler tubes. These tubes must pass rigorous testing, including hydrostatic tests, flaring, and flattening tests, along with ensuring proper chemical composition and mechanical properties. They are delivered in a heat-treated condition.
Additionally, there are specific requirements regarding the microstructure, grain size, and decarburization layer of the finished steel tubes. According to the standard GB5310-95 "Seamless Steel Tubes for High-Pressure Boilers," the outer diameter ranges from 22-530 mm, with wall thicknesses varying from 20-70 mm. Cold-drawn (cold-rolled) tubes have an outer diameter of 10-108 mm and wall thicknesses between 2.0-13.0 mm.
The purification principle of hydrogen using a 15CrMo boiler tube operates on the idea that when hydrogen to be purified is passed through one side of the tube at temperatures between 300-500°C, it gets adsorbed onto the tube's walls. Palladium's 4d electron layer lacks two electrons, allowing it to form unstable chemical bonds with hydrogen (a reversible reaction). Under palladium's influence, hydrogen ions are created with a radius of approximately 1.5 × 10â»Â¹âµ m. Given that palladium's lattice constant is around 3.88 × 10â»Â¹â° m (at 20°C), protons combine with electrons to form hydrogen molecules again, escaping through the other side of the tube. Since undissociated gases cannot permeate the surface of the tube, this process yields high-purity hydrogen.
The representation of a 15CrMo boiler tube involves several conventions. The first two digits in the steel designation denote the average carbon content in ten-thousandths, such as in 40Cr. Major alloying elements are expressed as percentages, except for microalloying elements. If the average alloy content is below 1.5%, only the element symbol is listed without specifying the exact amount, though occasionally a "1" might follow the symbol for clarity. For instance, "12CrMoV" indicates a chromium content of 0.4-0.6%, whereas "12Cr1MoV" signifies 0.9-1.2%. When the alloy content exceeds 1.5%, the percentage is explicitly stated, such as in 18Cr2Ni4WA. Microalloying elements like vanadium (V), titanium (Ti), aluminum (Al), boron (B), and rare earths (RE) are always included in the designation, even if their quantities are minimal. For high-quality steel, an "A" is appended to differentiate it from regular high-quality steel. Special-purpose alloy steels may feature a prefix or suffix indicating their application, like ML30CrMnSi for riveting screws.
Alloy pipes and seamless pipes share some connections but differ significantly in definition. An alloy pipe is identified by its material composition—essentially, it’s a pipe made from alloy steel. In contrast, a seamless pipe is defined by its manufacturing process, distinct from seamed pipes, which include straight-seam and spiral-welded varieties.
To calculate the weight of a 15CrMo boiler tube per meter:
\[
[(\text{outer diameter} - \text{wall thickness}) \times \text{wall thickness}] \times 0.02466 = \text{kg/m}
\]
This formula helps determine the weight per meter of the tube, which is crucial for engineering applications and logistics planning.
Glass And Window Film,Glass Pe Protective Film,Waterproof Window Glass Pe Film,Window Glass Film
Wuxi Xinhao Protective Film CO.,Ltd , https://www.cotton-balewrap.com