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Deep Precision Industries, Rohtak Work Instruction For Thread Laps

This work instruction outlines the procedure for evaluating thread laps in rolled parts after or before heat treatment. It provides details on sample preparation including cutting, mounting, grinding, polishing and etching samples to be examined under a microscope. The instruction specifies using a metallurgical microscope at minimum 100x magnification to examine thread laps and accept parts based on criteria in ISO and ASTM standards for different materials. It also lists common metallographic etchants and their compositions for microstructure examination of steel, stainless steel and nickel alloys.

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525 views2 pages

Deep Precision Industries, Rohtak Work Instruction For Thread Laps

This work instruction outlines the procedure for evaluating thread laps in rolled parts after or before heat treatment. It provides details on sample preparation including cutting, mounting, grinding, polishing and etching samples to be examined under a microscope. The instruction specifies using a metallurgical microscope at minimum 100x magnification to examine thread laps and accept parts based on criteria in ISO and ASTM standards for different materials. It also lists common metallographic etchants and their compositions for microstructure examination of steel, stainless steel and nickel alloys.

Uploaded by

vipulsharma655
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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DEEP PRECISION INDUSTRIES, ROHTAK WI No.

WI/LAB/04/103
Rev. No. 00
WORK INSTRUCTION FOR THREAD LAPS EFF. Date 28.10.2020
Page 1 of 2
1. PURPOSE:

To lay down the procedure for evaluation of thread laps of rolled parts after or before heat treatment.

2. SCOPE:

Fasteners (finish & semi finish)

3. REFERENCE STANDARD:

ASTM E3/ ASTM E407/ISO 6157-3/ASTM F788

MASTER EQUIPMENT:

Metallurgical Microscope.

4. SAMPLE PREPARATION:

 Take sample minimum 02 nos clean with HCL (50% V/V) for max. 01 minute & wash it.
 Visual Inspect the samples with zoom microscope at 10-40X magnification.
 Locate Laps area & marked it.
 Cut samples longitudinally from marked area through threaded section.
 Cut slowly with abrasive cutter & ensure proper cooling during cutting.
 Make mould with mounting press.
 Grind the sample on belt grinder to make both sides are parallel.
 Do polish of molded sample on grit no 220~1200 emery paper .
 Change direction of polishing by 90° on each & every grit no paper.
 Do final polishing using with alumina grade – I/diamond paste.
 After obtaining mirror finish, clean specimen with water.
 Select the etchant from ASTM E407 as per material grade ( As per clause 6).
 Etch the specimen if required as per method given in ASTM E407 ( As per clause 6).

5. METHOD OF TESTING:

 Examine thread laps with microscope at min 100X.


 Accept the part as per criteria given in ISO 6157-3/ASTMF788.

6. Micro etchants:

S. No. Etchant Composition Use


1. Nital 2-5 ML HNO3+95-98 ML H2O For microstructure of Fe base alloy steels.
2. Kalling’s Reagent 2 Gm CuCl2+40 ML HCl+40-80 ML For Stainless Steels and Ni base alloys
DEEP PRECISION INDUSTRIES, ROHTAK Document No. WI-7644
Rev. 00
WORK INSTRUCTION FOR THREAD LAPS Issued Date 01.09.2014
Page 2 of 2
Methanol

7.0 REVISION HISTORY:

Revision No. Revision Date Amendment Page

ISSUED &
PREPARED
VERIFIED & CONTROLLED
BY: DEPTT. HEAD
APPROVED BY: M.R.
BY: S.M.E. / FUNC.
ISSUE/REV. NO. : HEAD
ISSUE/REVISION DATE :

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