This article provides a practical guide to controllable pitch propellers (CPPs) for tugs, research vessels, offshore vessels, and Ro-Ro ships. It explains core advantages such as improved maneuverability, constant-speed main engine operation, shaft generator compatibility, and reduced engine wear. The guide outlines CPP system composition and classification, then details common hydraulic and pitch-control faults—including oil leakage, water ingress, unstable pitch, slow response, and abnormal noise or vibration—with troubleshooting steps. It also reviews industry trends toward electric drive, digital-twin-based intelligent pitch control, model-based diagnostics, and material evolution. The conclusion highlights stainless steel CPP blade and hub manufacturing for diameters below eight meters, using 1Cr13 martensitic stainless steel, austenitic stainless steel, and 12Kh18N10T for Arctic ice routes.

For reciprocating compressor cylinders operating in highly corrosive environments, 17-4PH martensitic stainless steel is the ideal material choice to meet HRC 30-34 hardness requirements. However, applying traditional complex three-layer water jacket structures to stainless steel results in severe casting defects, such as sand core sintering and shrinkage porosity. While the industry typically compromises by adopting a two-layer structure, this sacrifices the continuous water circulation and cooling efficiency. This article details TOTEM's engineering practice: by implementing a specific structural layout, we achieved effective communication between the water cavities without significantly increasing casting thermal joints. This solution successfully restores the circulating cooling path while ensuring the internal density of the casting, providing a reliable manufacturing path for complex stainless steel cylinder blocks.

This article compares the traditional three-layer structure and systematically analyzes the advantages of the two-layer structure for stainless steel compressor cylinder blocks in casting process, cooling efficiency, strength, sand removal and maintenance, and reliability. It serves as a reference for the selection and design of medium- and high-pressure, high-speed reciprocating compressors.

This technical guide covers food-grade fine-tooth rollers and chocolate refining roller shafts, from fine-tooth shearing and particle-size control to Ra 0.1–0.4 μm surface roughness and centrifugal-cast bimetallic composite manufacturing. Learn how these technologies support 15–20 μm chocolate grinding, cocoa bean crushing, nut and grain processing, and ultrafine grinding of nut butter and sesame paste.

This article explains how H1150M heat-treated 17-4PH stainless steel piston rods are used in gas reciprocating compressors. It covers core functions, structural design, material selection for normal, corrosive, and special conditions, the H1150M heat treatment route, WC coating, thread rolling, precision grinding, and inspection for acid gas and NACE MR0175 service.