SCHEDULE – B4 SCHEDULE – B4
MATERIAL SPECIFICATION NOTE-1 METALLURGY UNIT, WANAKBORI THERMAL POWER STATION MSN No.DATE : 14.06.12
COMPONENT: Centrifugally Cast REVISION- 00 DATE:-14.06.12 Inserted Grinding Rollers in Improved / Sintercast metallurgy SHEET. 01 of 05
BRIEF DESCRIPTION: You shall have to Design, Manufacture & Supply of the Centrifugally Cast Inserted Grinding Rollers (1 Set = 3 Nos.) in the Improved / Sintercast metallurgy for all Coal Mills of 210/120 MW to the Presently installed & in service. The specified inserted Grinding Rollers must be Suitable for Worst Coal Analysis mentioned here under and Guaranteed for 6000 Running Hours. Ultimate Analysis: % By Weight. Moisture. 15.00 Ash. 40.00 Carbon. 33.05 Hydrogen. 2.49 Sulphur. 0.30 Oxygen (diff.). 7.69 Nitrogen. 0.68 Higher Heating Value Kcal / kg. 3300 Grind ability Index HGI. 50 Centrifugally Cast Inserted Grinding Rollers in Improved / Sintercast metallurgy for Coal Mills of 210/120 MW shall be manufactured by Centrifugal Casting Machine. It should be of Composite Construction with ceramic padded Hard Insert Embedded in centrifugally cast SG Iron. Hard Inserts shall be formed Primarily of Chromium Carbides embedded with ceramic in Highly Wear Resistant Mass. A. PROCESS / PROPERTY REQUIREMENTS: i. REFERENCE STANDARD AND DEVIATIONS: The Indian Standard IS: 4771-1985 shall be Reference Standard (Ref, Std.) for All Purposes, except Chemical Composition and Hardness unless otherwise mentioned. Chemical Composition and Hardness are modified as iii & iv below respectively. ii.
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CASTING PROCESS: Centrifugally Cast inserted Grinding Rollers in the Improved / Sintercast Metallurgy is to be manufactured by Centrifugal Casting Process.
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iii.
CHEMICAL COMPOSITION:
iv
The Chemical Composition of Centrifugally cast Inserted Grinding Rollers in the Improved / Sintercast Metallurgy shall be in the Range of: Carbon (C) Chromium (Cr) Molybdenum (Mo) Nickel Manganese (Mn) Silicon (Si)
2.3 - 3.4 %. 18 - 27 %. 0.3 -2.5 %. 0.3-1 % 1.5 % max. 1.0 % max.
The Indian Standard IS: 1865 shall be Reference Standard (Ref, Std.) for SG Iron. Respectively Chemical Composition of S.G. iron of the Centrifugally Cast Inserted Grinding Rollers in the Improved / Sintercast Metallurgy shall be in the Range of: Carbon (C) Magnesium (Mg) Manganese (Mn) Silicon (Si)
iv.
v.
vi.
vii.
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3.2 - 3.5 %. 0.04 – 0.07 %. 0.3 % max. 2.5 % max.
The above Chemical Composition does not absolve you from Guarantee Responsibility. You shall have to submit the „Laddle‟ Analysis of Each heat the Rollers to GSECL. HARDNESS: The Hardness of Centrifugally Cast Inserted Grinding Rollers in the Improved / Sintercast Metallurgy shall be in range of 60 to 66 HRC. The Hardness shall have to be measured on Minimum Three Insert per Roller. Hardness of Spheroidal Graphite Iron Material shall be 180 BHN min. MICROSTRUCTURE: Microstructure of the inserts of Centrifugally cast Inserted Grinding Rollers in improved / Sintercast metallurgy shall consist of discontinuous Carbides in the matrix of Martensite. HEAT TREATMENT: The Heat Treatment of centrifugally cast inserted grinding roller in Improved / Sintercast metallurgy shall be Heating and soaking at a o o Temperature in the Range of 980 C to 1060 C followed by Air cooling. DYE PENETRANT TESTING: The Entire External Surface of Each Centrifugally cast inserted grinding rollers in Improved / Sintercast metallurgy shall have to be examined for through Dye Penetrate Test using Good Quality Chemicals. You shall have to submit Test Certificate for this Examination. No significant defect should be there which may affect performance of the roller
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ULTRASONIC FLAW DETECTION: Minimum 10% of the Total Nos. of the centrifugally cast inserted grinding rollers shall have to be examined by Ultrasonic Technique for Detection of Internal Flaws. All Examined Grinding Rollers shall be Free from „Significant‟ Internal Flaws. RESIDUAL MAGNETISM: All Centrifugally Cast Inserted Grinding Rollers in the Improved / Sintercast metallurgy shall be free from Any Type of (Residual) Magnetism. RED – OXIDE / PAINT: Red-Oxide shall be applied only after final inspection, QUALITY ASSURANCE MEASURES: STAGE INSPECTION: It will be essential that You shall have to keep GSECL informed about their Production Schedule 15 days in advance (Particularly Pouring, Heat Treatment) so that GSECL can arrange Stage Inspection. You need not discontinue your Production schedule because of Absence of GSECL‟s Representative unless it is to be instructed or agreed upon. “FIRST SAMPLE” STAGE INSPECTION: It will be essential for you to get All Stages inspected for the First Sample of Inserts & Grinding Roller by GSECL‟s Representative. Therefore, You shall arrange for Necessary Advance Intimations to GSECL for this Purpose. “SAMPLE APPROVAL”: In Addition to the Stage Inspections, it will be essential for you to submit First Sample of centrifugally cast inserted grinding roller in Sintercast / improved metallurgy to GSECL Site and obtain „Sample Approval‟ for Commencement of Bulk Production. „IDENTIFICATION MARK‟: It will be essential that all centrifugally cast inserted grinding roller in Sintercast / improved metallurgy have Clear- Cut Identification‟ for Traceability to their Heat, Heat Treatment Batch, your Name. Painting / punching is allowed for Identification (it should be such that it remains a Present at the time of Supply) Marks, IDENTIFICATION STATEMENT: You shall have to submit a Statement, along with Supply of Rollers regarding the list of Centrifugally Cast Inserted Grinding Rollers in Improved / Sintercast Metallurgy along with their Identification Marks and Details about Heat, Heat Treatment Batch They belongs to.
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CHEMICAL ANALYSIS: Party should pour the button sample for Spectro analysis and should arrange the spectro analysis in presence of GSECL Executives and should preserve the sample. CROSS VERIFICATION OF SAMPLES: Some of these submitted button Samples will be tested of GSECL end. In case the Result of Any button Sample tested at GSECL and differ significantly with the reported Chemical Analysis (refer B.iii) submitted by the party , the Entire Supply will be rejected. HARDNESS TESTING: REPORT: You shall have to submit a list of all Rollers and their All Measures Hardness Values (All Readings of All Three Locations and Not Average), along with Supply of the Rollers. HARDNESS LOCATIONS: All Hardness „Indentations‟ shall be left as they are. All Hardness Locations (where Measurement is made) shall leave to be encircled with suitable Paint such that they are apparent at the time of Supply. MICROSTRUCTURAL EXAMINATION: REPRESENTATIVE SAMPLES: You shall have to arrange preparation of Suitable „Representative‟ (Separately Cast and simultaneously Heat Treated) Samples for Micro Structural Examination, representing at least 10 % of Total Number of Grinding Rollers and get them examined for their Microstructure. REPORT: You shall have to submit a list of Roller whose Representative Samples are examined for their Microstructure VARIFICATION SAMPLES: You shall have to submit to GSECL, Minimum Half Number of Samples examined as above for Microstructure, along with Proper Identification (indication the Grinding Rollers they represent) at the time of Supply of the Grinding Rollers for Verification at GSECL End. ITEMS TO BE SUBMITTED WITH SUPPLY: You shall have to submit following items along with Supply Chemical Analysis. --- 100 % quantity DPT Report ----of 10% quantity
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SCHEDULE – B4 Ultrasonic Testing Report ------ 10% quantity Cross Verification Sample--------. 10% quantity Hardness Report ----------- 100% quantity Microstructure Report ----------. 10% quantity Microstructure Verification Samples -------. 10% quantity PERFORMANCE GUARANTEE for HPMS/MPSP System: The Criteria of The Performance Guarantee for each set of centrifugally cast inserted grinding rollers in Sintercast / improved metallurgy, Compatible High chrome Bull Ring segments and rotating Airport Ring Assembly shall be as follow. (1)
Guarantee: Life of Grinding Rolls and Bullring Segments (in set): 6000 hrs. The life of Airport ring assembly should be 18000 hrs
For Grinding rollers and Bullring segments ,free replacement if wear is more than 50 mm on Roll and 30 mm on Bullring Segments before logging 3000 hrs and prorata recovery between 3001 to 5999 hrs. For airport ring assembly, free replacement if fails before logging 9000 hrs. Prorata recovery between 9001 to 17999 hrs. The mill output should not fall below 17 +/- 5% TPH for the coal composition specified above. The rejection of mill should be less than 0.7%. These parameters should be measured at Full Load of the Unit during Guaranteed 6000 Running Hours for coal characteristics specified above You shall have to agree for the following Standard Conditions: If the Product fails prior to 50% of the Guarantee Life, it shall be replaced Free of Cost and if the Product fails after 50% but before 100% of the Guaranteed Life, then Pro Rate Rebate shall be given in terms of Supplying Equivalent Number of Grinding Rollers for the Shortfall Hours Life by the Party. This is applicable for One Time for Particular A/T. You shall have to submit performance Bank guarantee of 10% of total order value for the centrifugally cast inserted grinding rollers in Sintercast/ improved metallurgy , Compatible High chrome Bull Ring segments and rotating Airport Ring Assembly
Suptd. Engineer(MET) GSECL, WTPS
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