Heat Treatment and Metallurgy Lab

The Annealing process:- Annealing is a heat treatment process that changes the physical and sometimes also the chemical properties of a material to increase ductility and reduce the hardness to make it more workable Annealing steel consists of heating a metal above a critical temperature and then cooling at a rate that will produce a refined microstructure. Annealing is most often used to soften a metal after cold working, to improve machinability, or to enhance properties like electrical conductivity. Annealing works in  three stages  – the recovery stage, recrystallization stage and the grain growth stage. These work as follows: 1. Recovery Stage This stage is where the furnace or other heating device is used to raise the temperature of the material to such a point that the internal stresses are relieved. 2. Recrystallization Stage Heating the material above its recrystallization temperature but below its melting point causes new grains to form without any residual stresses....

The Normalizing Process Heat Treatment:- Normalizing heat treatment is a heat treating process used to provide uniformity in grain size and microstructure in some steel grades. Process:- Normalizing is the process of heating a material to a temperature above a critical limit and then cooling in open air. Normalizing maybe used as part of a 3 step heat treatment process for high strength steels. This is the first step followed by austenitizing/quenching and tempering. Recovery stage Recrystallization stage Grain growth stage Recovery Stage During the recovery stage, a furnace or other type of heating device is used to raise the material to a temperature where its internal stresses are relieved. Recrystallization Stage During the recrystallization stage, the material is heated above its recrystallization temperature, but below its melting temperature. This causes new grains without preexisting stresses to form. Grain Growth Stage During the grain growth, the new grains fully develop. Thi...

Heat Treatment Processes:- Heat treatment of  steels is the heating and cooling of metals to change their physical and mechanical properties, without letting it change its shape. improving formability, machining, etc. Heat Treatment Process Steps:- In simple terms, heat treatment is the process of heating the metal, holding it at that temperature, and then cooling it back. During the process, the metal part will undergo changes in its mechanical properties. This is because the high temperature alters the microstructure of the metal. And microstructure plays an important role in the mechanical properties of a material. Holding:- During the holding, or soaking stage, the metal is kept at the achieved temperature. The duration of that depends on the requirements. For example, case hardening only requires structural changes to the surface of the metal in order to increase surface hardness. At the same time, other methods need uniform properties. In this case, the holding period is long...

INCLUSION RATING TESTING:- Non-metallic inclusions process :- Non-metallic inclusions are chemical compounds and non metals that are present in steel and other alloys. They are the product of chemical reactions, physical effects, and contamination that occurs during the melting and pouring process. Sources of inclusions formation Non-metallic inclusions that arise because of different reaction during metal production are called natural or indigenous. They include oxide , sulfide , alumina silicate and Globular oxide .Singl Globular oxide Apart from natural inclusions there are also parts of Slag, refectories , material of a casting mould (the material the metal contacts during production) in the metal. Such non-metallic inclusions are called foreign, accidental or exogenous. Most inclusions in the reduction smelting of metal formed because of admixture dissolubility decreasing during cooling and consolidation. Non-metallic...

How to calculate ASTM grian size of microstructure which have a scale bar? Grain size analysis is used as a quality control tool to ensure that alloys are manufactured to specification.  Some examples of this include verification of the heat treatment and condition of the alloy.  It can also be used to assist in understanding material failures. I have to find ASTM grain size, I would like to know is it a correct way to find the exact magnification of microstructure using scale bar . We have the microstructure test specimen of various metals at the lab. I used those microstructure test specimen to calculate the grain size using the                           Formula N*=2exp(n-1)  at magnification of 100 X measured in an area of 1 sq. inch. I want to know if it is the standard method for obtaining the average grain size. Can anyone attach the American Society for Testing and Materials document ASTM ...

Step Down ( macro-streak-flaw ) test of steel bar. Scope:- This Standard specifies a step-down test method, blue fracture test method and magnetic particle inspection method to assess the non-metallic inclusions in rolled or forged steel with the naked eye or using a magnifying glass with a magnification of not more than 10x. Test piece:- The test piece shall be machined to the dimensions given below in figure table 1 The machined surface shall not be rough but shall be fairly smooth. Test Procedure Process :- Sample preparation are complete then ,sample Deep in hydro cloric acid (HCL) temperature 70~80 Degrees centigrade for 1 Hrs. After process are complete then clean with hot & cold water . Method of Examination:- The length and the number of flaws shall be determined under good illumination cither with an unaided eye or with low magnafication 15x Terminology:- A:- For the purpose of this standard the streak flaw shall mean defects arising from n...

Compressive Strength:- Compressive strength is an effective way of measuring how much load a surface or material can bear. for this sort of strength is performed by exerting force downward on top of the objectequal and opposite force exerted upward on the bottom when L/D > 5,Buckling when L/D > 2.5, Shearing when L/D > 2.0 and friction is present at the contact surfaces,Double barrelling when L/D < 2.0 and friction is present at the contact surfaces, Barrelling when L/D < 2.0 and no friction is present at the contact surfaces, Homogenous compression. Compressive instability due to work-softening material. The compressive stress formula is:- CS = F ÷ A Compressive Strength = Load / Cross-sectional Area where  CS  is the compressive strength F is the force or load at point of failure and  A  is the initial cross-sectional surface area