Ad
related to: a-ferrite high temperature
Search results
Results from the WOW.Com Content Network
Below 912 °C (1,674 °F), iron has a body-centered cubic (bcc) crystal structure and is known as α-iron or ferrite.It is thermodynamically stable and a fairly soft metal. α-Fe can be subjected to pressures up to ca. 15 GPa before transforming into a high-pressure form termed ε-Fe discussed below.
In steel it produces a bainite microstructure whereas in cast irons it produces a structure of acicular ferrite and high carbon, stabilized austenite known as ausferrite. It is primarily used to improve mechanical properties or reduce / eliminate distortion. Austempering is defined by both the process and the resultant microstructure.
The metal is heated into the austenite region of the iron-cementite phase diagram and then quenched in a salt bath or other heat extraction medium that is between temperatures of 300–375 °C (572–707 °F). The metal is annealed in this temperature range until the austenite turns to bainite or ausferrite (bainitic ferrite + high-carbon ...
Ferritic stainless steels exhibit a ductile-brittle transition temperature (DBTT) which reduces its toughness at lower temperatures. [9] They are also susceptible to 475 °C embrittlement which results in embrittlement and a loss of plasticity when heated in the range the range of 250 to 550 °C (480 to 1,020 °F). Ferritic stainless steels ...
Steel with a high carbon content will reach a much harder state than steel with a low carbon content. Likewise, tempering high-carbon steel to a certain temperature will produce steel that is considerably harder than low-carbon steel that is tempered at the same temperature. The amount of time held at the tempering temperature also has an effect.
The martensitic reaction begins during cooling when the austenite reaches the martensite start temperature (M s), and the parent austenite becomes mechanically unstable. As the sample is quenched, an increasingly large percentage of the austenite transforms to martensite until the lower transformation temperature M f is reached, at which time ...
At a pressure of 13 GPa and room temperature, the body-centered cubic (BCC) ferrite powder transformed to the HCP phase in Figure 1. When the pressure was lowered, ε-Fe transformed back to ferrite (α-Fe) rapidly. A specific volume change of −0.20 cm 3 /mole ± 0.03 was measured.
At lower coiling temperatures, pearlite forms with finer lamellar spacing, resulting in enhanced mechanical properties due to the finer distribution of ferrite and cementite layers. Conversely, at higher coiling temperatures, pearlite forms with coarser lamellae, and a smaller amount of pearlite is observed as coarse cementite particles tend to ...
Ad
related to: a-ferrite high temperature