1Cr5Mo (normalizing) metallographic diagram

An Investigation of the Microstructure of 1Cr5Mo Steel

The 1Cr5Mo steel is a low-alloy martensitic steel. It has a combination of excellent mechanical properties, weldability, and resistance to oxidation and carburization. This has made it one of the most widely used low-alloy steels. In this paper, we present our investigation of the microstructure of 1Cr5Mo after being subjected to a normalizing heat treatment. The material was examined through optical microscopy, focused ion beam scanning electron microscopy, and X-ray diffraction.

Optical examination of the microstructure of the 1Cr5Mo steel by using a light microscope revealed a typical microstructure of ferrite and pearlite. The ferrite had a lamellar structure, with primary and secondary ferrite grains present in the microstructure. The pearlite had a globular structure, with a high percentage of primary ferrite grains present. Mill scale and other precipitates were also found in the microstructure.

Focused ion beam scanning electron microscopy revealed that 1Cr5Mo steel microstructure underwent a significant change during normalizing heat treatment. The primary ferrite grains decreased in size and changed in shape, while the secondary ferrite grains increased in size. The addition of the precipitates increased the interlamellar spacing, which further reduced the size of the primary ferrite grains.

X-ray diffraction revealed that the precursor phases in the 1Cr5Mo steel microstructure changed upon normalizing heat treatment. The ferrite and pearlite phases transformed to carbides and oxides, which were present in large clusters in the microstructure.

The findings of our investigation show that normalizing heat treatment significantly affects the microstructure of 1Cr5Mo steel. The ferrite and pearlite phases changed in size and shape, while precipitates were formed throughout the microstructure. The transformation of the precursor phases to carbides and oxides further contributed to the changes observed. We expect that further study of 1Cr5Mo steel and its microstructure should lead to a better understanding of its properties and behavior.

15Cr5Mo is a alloy steel consisting mainly of Chromium and Molybdenum. It has a composition of 15 percent chromium, 5 percent molybdenum, 0.2-0.6 percent carbon, with trace amounts of other elements. Its properties lie between those of Cr-element and Mo-element steels, and it is mainly used as a structural steel in power plants.

15Cr5Mo is produced by normalizing and tempering at high temperatures. The normalizing temperature is between 860°C and 900°C, and tempering temperature is between 450°C and 540°C. The steel has sufficient high-temperature strength and thermal fatigue resistance, thus allowing for safe design with minimum wall thickness.

Microscopic analysis of the 15Cr5Mo alloy steel shows that phase equilibrium between austenite and ferrite phase occurs at high temperatures. The microstructure consists of primary phases and secondary phases, such as delta ferrite and pearlite. After normalizing, the spheroidizing carbide is evenly distributed, and there are a certain number of carbides along grain boundaries and at the grain boundaries of ferrite.

15Cr5Mo alloy steel is mainly suitable for places with high temperatures and high pressure, such as turbine discs, turbine shafts, and other pressure vessels, flanges and valves. Its creep and oxidation resistance are superior to normal Cr-Mo steel, thus making it suitable for high temperature and low pressure environments, such as flues and hot air ducts.