Boron is the most important alloying element in the boron steel. Its main effect is to improve the hardenability of the steel, and thus can increase the size of the steel hardenability, or improve after quenching steel sectional microstructure and properties of uniformity.
About the mechanism on the boron to improve hardenability have been proposed a variety of claims, wherein the more consistent understanding is: because boron delayed ferrite nucleation process (but does not affect the thermodynamic properties of the austenitic or ferritic matrix, also means that the boron can reduce the nucleation rate of the ferrite, but does not affect the growth rate as well as the rate of formation of pearlite and martensite) increasing steel’s hardenability. Austenite grain boundary segregation of boron atoms reduce the differences of the various mechanisms by what means is that boron to postpone the nucleation rate of ferritic, which has: boron reduced the self diffusion capacity of the iron in the austenite grain boundaries, The boron atom Segregation reduced nucleation position, the role of M23 6 boron carbide (B, C) and doctrine.
About the mechanism of boron improve the hardenability, scientists has conducted a lot of researches, and continues even in the current. The role of the boron to improve hardenability have many different features from the other alloying elements. There are (1) with a very strong ability to improve the hardenability. According to the metal powder supplier, 0.0010% to 0.0030% boron can be respectively equal to 0.6% manganese, 0.7% chromium, 0.5% molybdenum and 1.5% nickel, and therefore its ability to improve the hardenability of the above alloying elements hundreds of times or even thousands of times, and therefore only a small amount of boron can save a lot of expensive alloying elements.
(2) with the optimum content and the content is minimal. Usually alloy elements improve the hardenability effect and growth with its content in the steel is increased, but there is an optimum content range of boron powder, too much or too little of improving hardenability unfavorable, but this amount is very small, approximately 0.0010%, generally control in 0.0005% to 0.0030%.
(3) the effect of boron’s hardenability is related to the composition of the steel. Generally considered to carbon steel and alloy element content increasing, but the boron improve hardenability is decreasing. Therefore, low-carbon, low-alloy steel, boron hardenability effect is the most significant.
(4) the boron’s hardenability is related to austenitizing conditions. Early studies have shown that there is a special relationship between them, that in a particular austenitizing temperature, the hardenability effect of boron is good; when the temperature rises again, despite the austenite grain growth, the impact of boron’s hardenability will be dropped. Some recent studies have found that the a titanium fixed nitrogen, boron steel in a certain austenitizing temperature range almost no change in hardenability. These phenomena are associated with quenching of the alloy elements in general permeability effect austenitizing temperature relationship. The role of other alloying elements in addition to the boron, is often added some other alloying elements in boron steel, such as silicon, manganese, chromium, molybdenum, niobium, vanadium, etc. further improve the hardenability of steel and some other properties, such as strength, toughness, temper brittleness, fatigue properties, and corrosion resistance. Molybdenum can be greatly enhanced the boron hardenability, both with a composite role, especially when the appropriate ratio of the content of molybdenum and boron, steel can be obtained by controlled cooling bainite in a fairly wide range of cooling rate. Molybdenum - boron system the bainitic steel designed is based on this phenomenon. The niobium in the steel in a solid solution state having a composite effect with boron, produce a strong inhibitory effect on the austenite transformation. This effect of niobium - boron has been used in the controlled rolling, direct quenching of steel.
Source:http://www.mhcmp.com
The application of tungsten in various industries
Steel Industry Most of tungsten applied in the production of special steels. The widely used high-speed steel was containing 9-24% of tungsten, 3.8-4.6% of chromium, 1-5% of vanadium, 4-7% of cobalt, 0.7-1.5% of carbon.
Magic effects of coconut oil
According to records, coconut oil can be regarded as the nobility of skin care plant extracts. It was rich in exotic tension of tropical plants, which can enhance the contractile force of the pores, perfectly beautify and nourish the skin.
Exploring the Potentials of Nano-Aluminum Powder
Nano-aluminum powder, a material with remarkable properties due to its minuscule particle size, is revolutionizing various industries with its high reactivity and large specific surface area. Unlike its bulk counterpart, nano-aluminum powder begins to oxidize at a lower temperature of 550°C, compared to the 950°C oxidation point of ordinary aluminum. This lower ignition energy and full combustion without apparent cohesion make it a superior choice for applications requiring high energy and efficiency. The unique characteristics of nano-aluminum powder, such as faster burning rates and greater heat release, are largely influenced by its synthesis method, which determines its particle size, surface area, and shape.
