Table of Contents
What is the difference between hypo and hyper-eutectoid steel?
(a) A “hypoeutectoid” steel has a carbon concentration less than the eutectoid; on the other hand, a “hypereutectoid” steel has a carbon content greater than the eutectoid. The eutectoid ferrite is one of the constituents of pearlite that formed at a temperature below the eutectoid.
Is there any difference in microstructure for Hypoeutectoid steel and Hypereutectoid still?
In hypereutectoid steel, the equilibrium microstructure at room temperature contains proeutectoid cementite and pearlite (Fig. 6(d)). The main difference here with hypoeutectoid steel structure is that we obtain a continuous network of cementite, which separates each pearlite colony.
What is Hypereutectoid steel used for?
Hypereutectoid steels are commonly used as the tool materials, the relatively high carbon content determines the high volume fraction of carbides in these materials. The majority of the carbides are alloyed secondary ce- mentite.
Is Hypereutectoid steel brittle?
The hypoeutectoid steel is the most ductile and the ductility has decreased by a factor of three for the eutectoid alloy. In hyper-eutectoid alloys the additional, brittle cementite on the pearlite grain boundaries further decreases the ductility of the alloy.
What is pro eutectoid α iron?
Proeutectoid signifies is a phase that forms (on cooling) before the eutectoid austenite decomposes. It has a parallel with primary solids in that it is the first phase to solidify out of the austenite phase.
What is \%of C by weight in Hypo-Eutectoid steels?
Eutectoid steels contain 0.76 wt. \% carbon (in practice, steels with 0.75–0.85 wt. \% carbon are often classified as eutectoid steels). These steels form as a solid solution at any temperature in the austenitic range and all carbon is dissolved in the austenite.
What are microstructure of eutectoid Hypoeutectoid and Hypereutectoid steels obtained under equilibrium conditions?
The equilibrium microstructure of eutectoid steel obtained at room temperature is pearlite (Fig. Pearlite has properties between the soft ductile ferrite and hard brittle cementite. In hypereutectoid steel, the equilibrium microstructure at room temperature contains proeutectoid cementite and pearlite (Fig. 6(d)).
Which of the steels is Hypereutectoid steel?
12.03. 2.4 Vanadium and Boron Effects
| Steel | DI range |
|---|---|
| 1340H | 2.3–3.2 |
| 2330H | 2.3–3.2 |
| 2345 | 2.5–3.2 |
| 2512H | 1.5–2.5 |
Why hypereutectoid steels are not full annealed?
Because this excess cementite network is brittle and tends to be plane of weakness, full annealing should never be a final heat treatment process for hypereutectoid steels. The presence of a thick and hard grain boundary will also result in poor machinability.
Which Microconstituents of steel is hardest?
The equilibrium microstructure of eutectoid steel obtained at room temperature is pearlite (Fig. 6(c)) which is a mixture of two microconstituents named ferrite (α) and cementite (Fe3C); ferrite is very soft while cementite is a very hard constituent of steel.
How do you make martensite?
In certain alloy steels, martensite can be formed by working the steel at Ms temperature by quenching to below Ms and then working by plastic deformations to reductions of cross section area between 20\% to 40\% of the original. The process produces dislocation densities up to 1013/cm2.