45# MS Seamless Pipe Heat Treatment Process

45# MS Seamless Pipe is high quality carbon structural steel. It is commonly used material for machining. 45# grade is steel grade in china standard GB, in JIS Standard it is called S45C grade, in ASTM standard it is called 1045 grade, and in DIN standard it is called C45 grade. For its good comprehensive mechanical properties, 45# seamless tube is widely used in various important structural parts.

First of all, the chemical contents of 45# MS Seamless Pipe are much different from that of 20# Seamless Pipe. It contains C 0.42~0.50%, Si 0.17~0.37%, Mn 0.50~0.80%, Cr <=0.25% in chemical components. From its Carbon content and practical application, we see that its surface hardness is low, not wear – resistant. However, its surface hardness of parts can be improved by quenching and tempering.

45# MS Seamless Pipe can be used for producing medium and small carburizing, carbonitriding parts & forging parts, such as lever shaft, gear shift fork, gear, heavy mechanical lever, shackle and so on. And it can also be used to manufacture high-strength moving parts, such as turbine impellers and compressor pistons. Shafts, gears, racks, worms, etc.

45# MS Seamless Pipe has a carbon content of about 0.45%, containing a small amount of manganese, silicon, etc., high-quality carbon structural steel with low sulfur and phosphorus content. 45# MS seamless carbon steel pipe includes hot-rolled (extruded, expanded) and cold drawn (rolled) steel pipe, which is widely used in chemical, petroleum, textile, medical, food, machinery and other industries. During production, recommended heat treatment temperature for manufacturing 45# seamless tube is: normalizing 850, quenching 840, tempering 600. 45# steel is high-quality carbon structural steel, hardness is not high, easy to cut, mold is commonly used as a template, tip, guide column, etc., before using it, it needs to be processed by heat treatment.

1. Before 45# MSseamless carbon steel pipeis quenched without quenching, the hardness is greater than HRC55 (up to HRC62). The highest hardness for practical application is HRC55 (high frequency quenching HRC58).
2. 45# seamless pipeshould not be subjected to the heat treatment process of carburizing and quenching. After the quenching and tempering treatment of 45# MSSeamless Pipe, the parts have good comprehensive mechanical properties and are widely used in various important structural parts, especially those connecting rods, bolts, gears and shafts which work under alternating load. However, the surface hardness is low and it is not wear resistant. Tempering plus surface quenching can be used to improve the surface hardness of the part.

Carburizing treatment is generally used for heavy-duty parts with surface wear resistance and core impact resistance, and its wear resistance is higher than quenching and tempering + surface quenching. The surface has a carbon content of 0.8–1.2%, and the core is generally 0.1–0.25% (in a special case, 0.35%). After heat treatment, the surface can obtain high hardness (HRC58–62), low core hardness and impact resistance.

If carburizing with 45# MS Seamless Pipe is used, hard and brittle martensite will appear in the core after quenching, and the advantage of carburizing treatment will be lost. Nowadays, the materials seamless tube used in the carburizing process are not high in carbon content, and the core strength can reach 0.30%, which is rare in application. In practical application, these is seldom 0.35%, only introduced in textbooks. It can adopt the process of quenching and tempering + high-frequency surface quenching, and the wear resistance is slightly worse than that of carburizing.

The recommended heat treatment system for 45# MS seamless carbon steel pipe  is specified in GB/T699-1999: 850 degrees for normalizing, 840 degrees for quenching, 600 degrees for tempering, and the performance could reach yield strength ≧355 MPa. In GB/T699-1999 standard, 45# MS seamless carbon steel pipe should have physical performance such as tensile strength 600MPa, yield strength 355MPa, elongation 16%, section shrinkage is 40%, impact energy is 39J.

Wan Steel Group owns most advanced production lines for 45# /S45C/C45 seamless tube manufacturing. Please send us your detailed requirement, let us give you best solution for seamless carbon steel pipe.