Metallographic diagram of Q235 (slow cooling after carburizing at 950°C) carburizing treatment

Q235 carbon steel is a low-carbon steel alloy typically used in structural steel applications. It is a popular material for structural components, primarily due to its strength and formability. In certain applications, however, Q235 requires a heat-treatment step to increase its toughness and dimensional stability. This heat-treated Q235 steel is what is typically referred to as “Q235(950℃sensitized and slowly cooled)”.

Metallography is an effective method for inspecting the microstructural features of metals and alloys. Metallography is typically used to identify the composition and distribution of elements within a material and to evaluate how these features may or may not affect the materials expected performance. In the case of Q235(950℃sensitized and slowly cooled), metallography is used to identify and evaluate the changes that take place in the material’s microstructure when it is heat-treated.

To evaluate the effects of the Q235(950℃sensitized and slowly cooled) treatment on the material, a metallographic sample of Q235(950℃sensitized and slowly cooled) was prpared. The Q235(950℃sensitized and slowly cooled) sample was polished prior to testing and then mounted onto a scanning electron microscope (SEM) sample holder. The sample was then examined under high-quality magnification.

Under the SEM, it was possible to examine the Q235(950℃sensitized and slowly cooled) metallography and assess the changes that had taken place in the material’s microstructure. It was noted that the original, untreated Q235 steel contained a combination of ferrite and pearlite. Following the heat-treatment step, it was observed that the pearlite had transformed into a ferrite-cementite formation, with ferrite grains replaced with cementite. Furthermore, it was observed that carbon had diffused throughout the Q235(950℃sensitized and slowly cooled) grain structure, creating a uniform distribution of carbon-rich precipitates on the surface of the ferrite grains.

The results of the metallographic examination of the Q235(950℃sensitized and slowly cooled) sample showed significant changes in the microstructure of the material due to the heat treatment process. It was observed that the original combination of ferrite and pearlite had been replaced with ferrite-cementite, and that a uniform distribution of carbon-rich precipitates had been created on the surface of the ferrite grains. These changes indicate that the Q235(950℃sensitized and slowly cooled) heat-treatment process was successful in increasing the strength and dimensional stability of the material, confirming that the Q235(950℃sensitized and slowly cooled) heat-treatment process can effectively improve the performance of Q235 steel in certain applications.

Q235 steel is one of the most common materials in the world, used for countless projects in various fields. The steel is especially renowned for its mechanical properties, because it is easily processed and welded. It is also for its resistance to corrosion. As a result, it is widely used in a variety of industries, including construction, vehicle production and container manufacturing.

To increase its stability, Q235 steel is often tempered through heating, followed by slow cooling. This process is known as Q235(950℃ carburizing) carburizing treatment. It creates a layer of carbon on the surface of the steel and increases its hardness, strength and resistance to wear and tear.

When undergoing this process, the metal is heated at a temperature of 950℃ and the carbon enters the metal and bonds to the iron atoms. The Q235 steel is then slowly cooled in order to prevent the carbon atoms from escaping.

Observing the metal through metallography allows for a better understanding of the structural changes that occur during the carburizing treatment.

The metallographic sample of the metal shows a uniform, polygonal ferrite grains with a small amount of martensite and/or pearlite in the background. The relatively large ferrite grains provide the steel with better stability and strength, allowing it to withstand higher temperatures and stresses. The martensite and pearlite provides the steel with malleability and improve its resistance to corrosion.

Because of the entrapped carbon, there is also a large number of spherical and irregularly shaped pearlite particles around the ferrite. The carbon atoms trapped in the tiny pearlite particles give the steel greater hardness and strength. This makes the steel suitable for tough construction and manufacturing projects or applications that require wear and tear resistances.

Overall, Q235(950℃ carburizing) carburizing treatment improves the mechanical and corrosion resistance properties of the Q235 steel, thereby increasing its overall performance.