Industrial applications of chrome molybdenum steel include construction machinery, chemical processing equipment, and pharmaceutical manufacturing equipment. In addition, it is used as an alloying element in stainless steel used in food processing machinery, jet engines, and aircraft construction. Chromium molybdenum steel is cold-worked to increase its chromium content. Corrosion resistance and strength are better than those of stainless steel with the same carbon content. The production of chrome molybdenum steel is also resistant to phosphates and organic solvents.
Chromium molybdenum steel is available in a wide range of thicknesses, from 0.001 inches to 2 inches (1 mm to 50 mm). In terms of hardness and corrosion resistance, it is comparable to chromium molybdenum stainless steel. When welded into iron alloy steels or forgings, chromium molybdenum steel has excellent chemical and electrochemical properties. In addition to alloy steels, chromium molybdenum steel is suitable for high-temperature, high-strength applications. Among its applications are the casting of structural shapes, tubing, bearings, pipes, and alloys.
Chromium-molybdenum alloy steel (or chrome moly) is used in high-temperature and high-pressure applications. Due to its corrosion resistance and high-temperature and tensile strength, it is used in the oil and gas, energy, construction, and automotive industries.
What is the purpose of Cr and Mo?
Over the years, Mo has been a standard alloying element in creep-resistant steel that can withstand temperatures up to 530 C. Mo lowers the creep rate of steel and slows carbide coagulation and coarsening at high temperatures. Due to its high-temperature suitability and creep resistance, Mo-based steels are primarily used in power generation and petrochemical plants.
However, increasing the Mo content of the steel will not improve its properties because creep ductility decreases with increasing Mo. Furthermore, graphitization (the breakdown of iron carbides) occurs above 500°C. Mo-based steels are limited by these drawbacks.
A solution was found by alloying chromium with molybdenum. The CrMo steel has many advantages over Mo-based alloys, and it was the first steel that allowed steam temperatures in power plants to exceed 500°C.
Because of their combined properties (with a minimum Cr content of 9% and a minimum Mo content of 1%), this duo of alloying elements works so well. As an example, Mo gives the steel its strength and allows it to work at higher temperatures. Moreover, the Cr results in excellent oxidation and helps the steel resist corrosion better. In addition to providing good hardness penetration, the Cr content ensures uniform hardness.
Due to its additional strength and corrosion resistance, CrMo steel is used when mild carbon steel isn’t strong enough. Chrome moly has these advantages, which is why it is used in so many different applications.
It is possible to obtain significant corrosion resistance and toughness with chromium molybdenum steel that has a chromium content of 0.01 percent to 1.50 percent.
The high strength, corrosion resistance, and low conductivity of chrome molybdenum steel require continuous casting or short-time reduction annealing. A ton of chrome-molybdenum steel costs between $200 and $450. Its high chromium content prevents stainless steel from being used for motors or automobile engine cylinders, but its high strength makes it ideal for structural applications. Due to its low carbon content (0.3 percent), stainless steel is suitable for aircraft engines and shipbuilding. As it is manufactured by electrolytic smelting, it has a low chromium melting point of chromium and is relatively expensive. Stainless steel is tough, corrosion-resistant, and has high strength, but its high cost makes it unsuitable for many applications other than automotive and industrial ones.
Stainless steel is made from chrome molybdenum steel (CMS). It is also used in high-temperature applications. High-temperature applications benefit from the use of this steel. Chrome steel (CMS) is also known as stainless steel, chromium alloy steel, and AISI-1527. It is used to make stainless steel, but it can also be used to make aluminum and bronze. Chromium steel plate is produced by alloying chromium with molybdenum, while stainless steel is produced by alloying chromium with molybdenum.
Because chrome steel contains a small amount of carbon, it has a high hardness. Chromium is added to stainless steel to give it its various properties. It has a wide range of applications. As a result of their corrosion resistance, chrome steels can be used for many general purposes, including engineering and construction, oil exploration, water supply and wastewater treatment plants, industrial engines, cold-starving engines, etc. In the production of stainless steels, alloy additions differ from those in the production of non-stainless steels. Titanium (T) and vanadium (V) are two of them.
Depending on the process, these materials are added to steel to give it different properties. Chromium is the most common addition to stainless steels, except for carbon and high chromium stainless steels. Stainless steel is a corrosion-resistant alloy that can be used to repair or improve steel parts. In addition to its high cost, it is resistant to acids, oils, greases, and rust. Stainless steel particles are generally fine enough to not stick to smooth surfaces such as metal grilles or engine covers, so these materials are commonly used in automotive applications. It should be noted, however, that the finer the pore structure of stainless steel, the greater its corrosion and stain resistance. As a result of its high purity and remarkable performance in a wide range of applications, stainless steel is often used in high-end automobile engines.
Cobalt-based CrMo material case study
It has been shown that adding Cr to Mo-alloys allowed them to be used in a variety of high-temperature applications, and provided benefits not found in Mo-based steel. Researchers are constantly looking for ways to boost the performance of chrome moly and ensure it remains the material of choice in many industries in spite of this constant improvement of high-temperature steel.
An example of this is alloying CrMo with cobalt (Co). As an advanced material gaining widespread popularity in engineering and medical applications, cobalt chromium molybdenum (CoCrMo) alloy has been reviewed by Zaman et al. . Due to its high strength, toughness, wear resistance, and low thermal conductivity, this material is generally difficult to machine. The result can be rapid tool wear and shorter tool lifespans. CoCrMo’s characteristics and properties were discussed, as well as how these properties contribute to machinability.
As a result of the alloy’s high strength, toughness, wear resistance, and poor thermal conductivity, machining these materials is challenging and complicated. In light of the demand for cobalt-based CrMo alloys in many industries and applications, the authors conclude that more studies are necessary to overcome the problems of poor machinability. At present, chrome-moly steel is the steel of choice, but cobalt-based CrMo alloys may become the standard in the future if these machinability issues can be resolved.
Applications of Chrome Moly
Because chrome moly is stronger and more corrosion resistant, it is ideal for environments with elevated temperatures (beyond those of simple Mo-based steels). Chromium-molybdenum alloys can therefore be used in any industry or application that operates equipment at high temperatures. Oil and gas, energy, automotive, metal production, and forming equipment are among these industries. CrMo is also effective in salt-water applications due to its high-temperature tensile strength and corrosion resistance.
Molds, bicycle tubing, crack shafts, chain links, drill collars, machine shafts, and conveyors are all examples of equipment that uses chrome moly. Construction and manufacturing also benefit from the alloy’s properties. Creep strength, rigidity, hardenability, wear resistance, good impact resistance, ease of fabrication, and the ability to alloy in ways that make it “fit for use” in certain situations are some of these properties.