Molybdenum micro-alloyed weldable reinforcement steel has gained increased attention in foreign countries due to its high strength with good ductility and excellent weldability. The combination of high tensile strength and good ductility makes it suitable for many structural applications. The objective of this paper is to provide a comprehensive review of the mechanical properties of molybdenum micro-alloyed weldable reinforcement steels.
Molybdenum micro-alloyed weldable reinforcement steel contains high levels of molybdenum or molybdenum-containing alloys. Molybdenum micro-alloying increases the strength of steel significantly by forming extremely fine precipitates, which are grouped as carbides, nitrides, carbonitrides and oxides. These particles improve the strength of the steel by acting as strengthening agents. Molybdenum micro-alloying also improves the weldability, toughness and fatigue resistance of steel by forming small particles that react with hydrogen and prevent cracking.
Molybdenum micro-alloyed weldable reinforcement steels usually have a high tensile strength, typically greater than 435MPa. Tensile strength is a measure of the maximum stress a material can withstand before it deforms permanently. It is usually determined by tension tests carried out in accordance with an appropriate standard. High tensile strength is essential for applications involving high loading and/or very fine stresses.
Molybdenum micro-alloyed weldable reinforcement steels also have high yield strength, typically in the range of 350-500 MPa. Yield strength is a measure of the maximum stress the material can sustain before undergoing whole plastic deformation and failure. It is usually determined by performing a decreasing load compression test on standard-sized test pieces. High yield strength is essential in applications where the material will be under sustained load.
Besides, the ductility of molybdenum micro-alloyed weldable reinforcing steel is usually very good. Ductility is the ability of a material to deform without inelastic deformation. It is typically measured by determining the elongation at break of a standard-sized test piece. Good ductility is essential for applications where the material needs to undergo large deformations before failure.
Molybdenum micro-alloyed weldable reinforcement steels also have good weldability. Weldability is the ability of metal to form strong, durable welds that do not crack or warp. Generally, metals with high levels of molybdenum micro-alloying are considered to have good weldability. It is important for applications that require welds that will remain strong for a long time.
Finally, molybdenum micro-alloyed weldable reinforcement steels typically have good fatigue resistance. Fatigue resistance is the ability of a material to resist fracture under repeated loading and unloading cycles. Molybdenum micro-alloying increases the fatigue strength of steel by forming fine, uniform precipitates that act as strengthening agents.
In summary, molybdenum micro-alloyed weldable reinforcement steels possess a combination of high tensile strength with good weldability, ductility and fatigue resistance. This makes them suitable for many structural applications where high strength with good formability and weldability is required. This review has demonstrated that these steels possess a high level of mechanical properties suitable for these types of applications.
