Heat Treatment and Metallurgy Lab

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

Tensile test :- Introduce:- Tensile test property often are measure during development of new material and process , tensile property often are used to predict the behavior of a Material under forms of loading other than uniaxial tention. 1)-Tensile specimen and test machines. 2)- stress -strain curve , elastic versus plastic deformation. 3)-yield point , Ductility 4)-test methodology and analysis 5)-True stress and strain. Test methodology and data analysis:- 1.sample selection. 2.sample preparation.  3.Test setup. 4.Test procedure.  5.Data recording and analysis. 6.Reporting. Yield Strength Take the minimum yield in psi of the ASTM grade (see our Strength Requirements by Grade Chart for this value), multiplied by the stress area of the specific diameter (see our Thread Pitch Chart). This formula will give you the ultimate yield strength of that size and grade of bolt. Shear Strength :- First, find the ul...

Brinell hardness tester procedure:- BRINELL HARDNESS TESTING The Brinell hardness test is used for larger samples in materials with a coarse or inhomogeneous grain structure. This page describes the Brinell hardness test in detail and gives you practical information on how to apply it. Brinell Test Machine Description:- The Brinell Hardness Tester consists of a loading system, the main screw, and a dial gauge. The loading system consisting of weights, leavers and a hydraulic dashpot and a plunger arrangement is enclosed in the cast iron body of the machine. The main screw is also protected from extraneous elements by a rubber bellow. It carries the test table on its top to hold the specimen and is actuated by a hand at the base. The machine is provided with two ball indenters (of sizes 2.5mm&5mm) to transmit the test load on to the specimen DEFINITION OF THE BRINELL HARDNESS TEST:- Today, the Brinell test is performed using a Brinell hardness test unit. The machine presses a tungst...

Jominy end-quench test :- Jominy end-quench test is quite simple and easy test, and is thus, almost universally employed for the determination of hardenability. For this test, a slightly oversized bar of steel is normalisad at about 66°C (≈ 150°F) above Ac 3 , and then machined to the final dimensions of 4″ (102 mm) long and 1″ (25.4 mm) diameter. Machining removes any decarburised layer formed in the normalising treatment. The machined bar is put inside a closed box, half-filled with cast iron chips to prevent decarburisation, and then austenitised for 30 minutes at about 22-23°C above Ac 3 . Standard Jominy-test specimen and fixture :- Meanwhile, the special water-quenching device is kept ready. In this device, the diameter of the pipe opening is 1/2 inch. Specimen holder is such that the bottom of the specimen remains at 1/2 inch above the nozzle. The constant pressure of the water is such that the height of the impinged jet is 2 inch. The water temperature is 75 ± 5°F. ...

A microscope is an instrument used to see objects that are too small to be seen by the naked eye. Microstructure  is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope 🔬 The purpose here is to help identify the microstructures in steel using simple techniques based on the atomic mechanisms by which phases grow from austenite. Apart from their aesthetic beauty, microstructures become meaningful when examined in the context of their metallurgical theory. The symbols used to represent each phase are as follows: Phase Symbol Austenite γ Allotriomorphic ferrite α Idiomorphic ferrite α I Pearlite P Widmanstätten ferrite α w Upper bainite α b Lower bainite α lb Acicular ferrite α a Martensite α' Cementite θ θ Austenite:- Austenite has a cubic-close packed crystal structure, also referred to as a face-centred cubic structure  Ferrite:- Ferrite has a body-ce...

INFORMATION. Rockwell hardness test, a differential-depth method, the residual depth of the indent made by the indenter is measured.  The deeper a defined indenter penetrates at a defined test force into the surface of a workpiece (specimen), the softer the tested material. In the Rockwell method, the total test force is applied in two stages. This allows the impact of specimen surface roughness (e.g. grooves in the specimen) and measuring errors caused by backlash in indentation depth measurement to be eliminated. THE INDIVIDUAL ROCKWELL METHODS ARE DISTINGUISHED FROM EACH OTHER AND. The five resulting Rockwell methods use five different indenters (diamond cone with 120 o  curvature or a hard metal ball made from tungsten carbide with diameters of: 1/16",1/8",1/4",1/2") and six different total test forces (15, 30, 45, 60, 100, 150 kgf).. This results in 30 different - standardised according to ISO 6508 and ASTM E18 – Rockwell scales (e.g. A, B, C, 30N, ...

Case depth  is the thickness of the hardened layer on a specimen. Case hardening improves both the wear resistance and the fatigue strength of parts under dynamic and/or thermal stresses. Hardened steel parts are typically used in rotating applications where high wear resistance and strength is required. The characteristics of case hardening are primarily determined by surface hardness, the effective hardness depth and the depth profile of the residual stress. Gears and engine parts are examples where hardening is used. Effective case depth is the depth up to a further point for which a specified level of hardness is maintained . Total case depth is the depth to a point where there is no difference in the chemical or physical properties. Case depth testing often involves performing a series of hardness impressions from the edge of the specimen towards the center. The hardness progression is plotted on a graph and the distance from the surface to the hardness limit (HL) ...

Getting together SAMPLE PREPARATION:- Selecting a representative sample of the materials Sectioning the sample to avoid altering or destroying the structure of interest Mounting the section without damage to the test sample Grinding to achieve a flat sample with a minimum amount of damage to the sample surface Polishing the mounted and ground sample Etching in the proper etchant to reveal the microstructural details SELECTING Selecting a representative test sample to properly characterize the microstructure or the features of interest is a very important first step. For example, grain size measurements are performed on transverse sections, whereas general microstructure evaluations are performed on longitudinal sections. Therefore, it is important to provide the laboratory with information about the orientation or the rolling direction of the test specimen. SECTIONING Test samples are carefully sectioned to avoid altering or destroying the structure of the materials. If an abrasive saw...