Heat Treatment and Metallurgy Lab

Optical emission spectroscopy using arc and spark excitation (Arc Spark OES) is the preferred method for trace metal analysis to determine the chemical composition of metallic samples. This process is widely used in the metal making industries, including primary producers, foundries, die casters and manufacturing. Optical emission spectrometry involves applying electrical energy in the form of spark generated between an electrode and a metal sample, whereby the vaporized atoms are brought to a high energy state within a so-called "discharge plasma". These excited atoms and ions in the discharge plasma create a unique emission spectrum specific to each element, as shown at right. Thus, a single element generates numerous characteristic emission spectral lines.

Carbonitriding is a heat treatment process by which carbon and nitrogen (via ammonia gas) permeate the surface layer of steel components. The process involves temperatures of around 850°C followed by quenching in oil or gas solutions. Successful completion of this process will grant the steel components a variety of beneficial properties, most notably increased wear resistance Carbonitriding: the diffusion of carbon and nitrogen atoms into the surface of a metal to increase hardness; nitrogen is usually added to the endothermic atmosphere Heat Treatment: The temperature used for carbonitriding should be around 850°C (1550°F). This is lower than the temperature used for carburizing, and the time for which the part will be heat treated for is shorter as well. These lower temperatures used for carbonitriding compared to carburation also means there is less distortion of the part, especially during quenching. However, this is a higher temperature than what is used for standard nitriding...

  Case hardening Process Case hardening is a material processing method that is used to increase the hardness of the outer surface of a metal. Case hardening results in a very thin layer of metal that is notably harder than the larger volume of metal underneath of the hardened layer. - It is mainly used on low-carbon steels. The part is heated to 871–954 °C (1600–1750 °F) - Attempt to harden an entire metal object. One reason is efficiency. Less energy and less time are required to heat the outermost surface of a metal as opposed to its entire cross section. - A hard outside shell and a more ductile interior. What Types of Metals Can Be Case Hardened? Metals that can be case hardened are generally limited to ferrous materials, although there are special cases such as the Nitriding of some titanium or aluminum alloys. The ferrous metals commonly case hardened are. Gears Fasteners Camshafts Rods Pins   --BENEFITS OF CASE HARDENING Creating a more durable product Increases wea...

HEAT TREATMENT  SOAKING OR HOLDING HEATING CONTROLLED COOLING HEATING CYCLE

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

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, ...