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High Strength, Corrosion Resistant MITC TMT BARS

View video clip of entire Production Process

   

Quality Control

 

First we receive the raw material and send all the samples to laboratory where our Quality Control In-charge check the quality of material as per IS or requirement. We basically recycle the steel. All kinds of steel scrap like Turning, Boring, Pig Iron, and Sponge Iron etc.

Scrap Yard:
Over here we segregate all the scrap according to their density. Also we need to carry out cutting, bundling of scrap so as to make it comfortable to efficient charging. All these segregated, processed scrap and sponge iron, pig iron etc. are stocked at the scrap yard. Other Ferro Alloys like Ferro Silicon, Silico Manganese, Aluminum etc. are kept in store. Samples of all the raw materials are sent to the laboratory where they check and approve the quality of the material as per; ISI standards.   

Using electro magnet and EOT Cranes (Electronically Operated Overhead Crane), this scrap is charged into the Induction Furnace. In the crucible this scrap gets heated due to the Induction and Inductance. The Induction gets generated because of power supplied to the copper, which is surrounded to the crucible (Fleming Right Hand Thumb Rule). The heat so generated is then transfer the steel scrap into liquid metal. We take one bath sample from the furnace when the furnace is 1/3 full. The sample is sent to laboratory for chemical analysis where our quality person checks c%, Mn%, S% and P% of the sample. These testing are carried out 3-4 times at different level of Molten Metal in the furnace. According to laboratory report we take corrective action and change scrap & sponge iron. Afterwards when the furnace is full, we take one another sample and send it to laboratory for testing. As per the laboratory report we have done final addition of Ferro alloys as per requirement of ISI standard and refining of metal. Then at a temperature of 1600 degree C to 1650 degree C the liquid metal is transferred to the refractory lined Ladle and liquid metal is then poured to continuous casting machine where we make billet and final sample is sent to laboratory where we check the C%, Mn%, S% and P% by Spectrometer and then billet is dispatched.

Testing Procedure

CARBON Combustion Method: In this process carbon checked by combustion at 1000 degree C to 1200 degree C in a stream of purified oxygen yields carbon dioxide which is absorbed by an alkali impregnated absorbent in Stroh lien Apparatus and calculated by difference of level. Temperature of combustion and state of division of the sample are important.

MANGANESEVolumetric Method: Ammonium Persulphate in the presence of Silver Nitrate dissolves the sample in diluted Nitric Acid and Manganese Oxidized. After precipitation of Silver Chloride, the cold solution containing Permanganic Acid is titrated immediately with Sodium Arsenate.

PHOSPHORUS  - Volumetric Method: The sample is dissolved in diluted Nitric Acid and after oxidation of carbonaceous matter phosphorus is precipitated as the yellow phosphomolybatate complex. The precipitate is collected and washed and the determination is completed volumetrically by titration with standard alkali and acid solutions.

SILICON Gravimetric Method: A solution of the sample in hydrochloric acid is evaporated to dryness and baked. The residue is extracted in hydrochloric acid and the insoluble silicon residue is collected by filtration, ignite and weighed as SiO2.

SULPHUR Combustion Method: The sample is ignited in a rapid stream of oxygen at 1300 degree and sulphur is converted to its oxides, which are driven forward in the gas stream and absorbed in hydrogen peroxide and titrated with sodium hydroxide.

SECTION WEIGHT: Take one-meter random sample and weigh by electronic balance for weight/meter.

Ultimate Strength, Yield Strength and Elongation: Mark the gauge length on sample and set in the jaw of Universal Tensile Strength Machine. When we start the machine and increase the load and sample stretched due to load. After certain load the meter reading stop for a while. This is Yield Load Point and afterwards when increase the load, sample get broken. This is Ultimate Load Point. We calculate the Yield Strength and Ultimate Tensile Strength with respect of load and area of bar.

For elongation we measure the increased gauge length and calculate the elongation % with respect to original gauge length.



SPONGE IRON

1) Determination of Total Iron.          Fe (T)
Take 0.2 gm. sample in 500 ml. Conical Flask.
Add 50 ml. Con. HCL. And boil it until it dissolve.
Add few drops of (Sncl2) in hot condition and ensure that color disappears.
Immediately cool the flask externally in water and add 25 ml. Hgcl2 5% solution ensure the silky white appearance in the flask.
Add 20 ml. Acid Mixture and dilute the solution to 250 ml. with distilled water.
Add 3-4 drops of B.D.S. Indicator.
Titrate against with 0.1 N K2Cr207 solution.
Calculation         
Fe(T) Vol. Of K2Cr207 consumed X N X 5.585
                                                 Wt. of sample.
   
2) Determination of Metallic Iron Fe(M)
Take 0.2 gm. In 250 ml. Beaker.
Add 3 gm. Hgcl2 and 100-ml. hot distilled water.
Cover the Beaker with water glass and boil for 10 min.
Cool and filter it in 500 ml. Conical Flask; wash the residue with hot water thoroughly.
Add 20 ml. acid mixture in filtrate
Add 3-4 drops of the B.D.S. Indicator.
Titrate against 0.1 N K2Cr207 solution.
Fe (M) %                 
Vol. Of K2Cr207 consumed X N X 5.585
                                                 Wt. of sample.
   
3) Determination of Ferrous Oxide Fe O
Take 0.2 gm. sample in 500 ml. Conical Flask.
Add 2 gm. Of Na2Co3 solid + 4 drops of HF + 20 ml. Con. Hcl +
20 ml (H3Po4) + 30 ml. distilled water.
Put in two-way tube and heat for 2 min.
Cool in atmospheric temperature.
Add 3-4 drops of B.D.S. Indicator.
Titrate against 0.1 N K2Cr207 solution.
X %                    
Vol. Of K2Cr207 consumed X N X 5.585
                                              Wt. of sample.
Fe O %              X % - Fe (M) % X 1.286
Where 1.286 = Fe O (M.W.) / Fe (M.W.)
=          7185 / 5585
=          1.28648
   
4) Degree of Metallization.
Degree of MZ % = Metallic Iron [Fe (M) / Total Iron] X 100
   
MITC TMT Bars have the following qualitites :
 
Standard Sizes & Normal Weight
 

MITC TMT TM

Dia (mm) Nominal Weight (Kg./Mtr.) Nominal Weight (Kg. Feet.)
8 0.395 0.120
10 0.618 0.188
12 0.888 0.271
16 1.578 0.481
20 2.466 0.752
22 2.984 0.910
25 3.856 1.172
28 4.836 1.473
32 6.318 1.925
 
Mechanical Properties
Properties Gr Fe 415 Gr Fe 500 Gr Fe 550
0.2% Proof Stree [N/mm2] Min
Ultimate tensile strength [N/mm2 Min]
 
430 - 460
500 - 570
520 - 560
590 - 640
560 - 590
650 - 670
% Elongation on 5.65 Area Min 20 - 24 18 - 24 16 - 22
Bend Test 180 where D = dia 2D 2D 2D
Rebend Test Bend 135.5 Rebend 157.5 4D 4D 4D
Stress & Ratio (TS/YS) Min 1.15 - 1.35 1.15 - 1.30 1.15 - 1.25
 
Chemical Composition
Grade C% Max Mn% Min Si% Max S% Max P% Max
Fe 415 0.25 0.55 0.30 0.055 0.055
Fe 500 0.25 0.60 0.30 0.050 0.050
Fe 550 0.25 0.75 0.30 0.045 0.045
 
Bend & Rebend Tests
SR. No. Parameter Size IS:1786/85 MITC TMT TM IS:1786/85 MITC TMT TM
1. Bend Upto & including 22 mm dia 3 x Dia 2 x Dia 4 x Dia 2 x Dia
    Over 22 mm dia 4 x Dia 3 x Dia 5 x Dia 3 x Dia
2. Rebend Upto & including 10 mm dia 5 x Dia 4 x Dia 5 x Dia 4 x Dia
    Over 10 mm Dia 7 x Dia 4 x Dia 7 x Dia 4 x Dia
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