Govt.

of India
Ministry of Railways
Research Designs & Standards Organization
Manak Nagar, Lucknow-226 012
QM-C-7.1/Coupler/00011
Inspection Plan (Check Sheet)
ITEM : Upgraded High Tensile Centre Buffer Coupler
: (Coupler Body, Knuckle &Yoke)
Spec. No. : WD-70-BD-10 (Rev.1)
Drg. No. & Alt. : SK-62724, Alt.23 (Item-1 & 10, Item-2 & Item-3)
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Firm’s Name

Date (period) of Inspection

Contract Details:

a. C o n t r a c t no. and date

b. Order placing authority

c. Specification no.

d. D r a w i n g no.

Quantity on order

Earlier Passed Qty.

Quantity offered for inspection on date.

Consignee.

Quality Control Manager of Inspecting Official of RDSO

M/s

Page 1 of 8
 SUMMARY OF RESULTS OF CENTRE BUFFER COUPLER & COMPONENTS (COUPLER BODY,
KNUCKLE & YOKE) Specification no. WD- 70-BD-10 (Rev.1) Drawing No.-SK-62724
Lot Size – 200 Nos.
SN Parameters Specified Value Observation
Max. Min.
1 Visual & No cracks, hot tears, cold shuts & weld cracks and
Operational Check
surface condition by SCRATA & Marking as per
(Sample size 10%)
drawing Components should operate freely in
assembled condition
2 Dimensional By go-no go gauges (As per RDSO Drawing listed
(Sample size 10%) at Sn. 12)
3 Physical Properties Gr. E (Minimum)
i)Tensile Strength 825 N/mm2
ii) YS 690 N/mm2
ii)Elongation 14%
iii) RA 30%
4 (i) Proof Static Max. permanent set in mm
tension test For knuckle at 181.5t - 0.76
For Coupler body at 317.5t - 0.76
Min. Ultimate Load
For knuckle 295t
For Coupler body 408t
(ii) Proof static test Max. Permanent set in mm.
of yoke At 340.2t 0.76
Min. Ultimate 408t
5 Chemical C-0.28-0.33 - Mn-0.60-.90- P-0.03- S-0.03- Si-0.40-
composition 0.60- Cr-0.50-0.80- Al-0.020-0.050- Ni-0.50-0.60
6 Microstructure of Fine tempered, Marten site.
Knuckle
7 Hardness Except Knuckle 241-311 BHN
For Knuckle 241-291 BHN
8 Impact Test Energy =3.50 kg. m at -40°C
(ASTM A 370)
9 Nil Ductility Test Value at - 57°C
(ASTM E604& E208)
10 Destructive test No blow holes ,slag inclusion, shrinkage etc.
11 Heat treatment Record to be checked.
12 Weight variation +5% to -3%
13 Radiographic test ASTM E446 Level II. Location of radiography test
(Sample size 10%) should be as per annexure – II of specification-
WD-70-BD-10 (Rev.1)
14 Gauging of Coupler As per Annexure-1 of specification no.WD-70-BD-10
And its Components (Rev.1)

Quality Control Manager of Inspecting Official of RDSO

M/s

Page 2 of 8
1. Visual, Operation & Marking: Sample size-10% or min 10 nos.

Specified Observed Value

1 2 3 4 5 6 7 8 9 10
Surface No cracks, hot tears, cold
defect shuts & weld cracks and
surface condition by SCRATA
Marking As per respective drawing
Operation Components should operate
Freely in assembled condition.

2. Dimensions: Sample size-10% or min 10 nos.

Specified Observed Value

1 2 3 4 5 6 7 8 9 10
As per respective drawing and
with gauges as listed by RDSO.
At Sno.12 of check sheet.

3. Physical Test: Sample size- one from each heat from Test Coupon.

Mechanical Observed Value

Properties
GRADE E (Min) 1 2 3 4 5 6 7 8 9 10
UTS 825
N/mm2

YS 690
N/mm2

Elongation 14%
RA 30%

Quality Control Manager of Inspecting Official of RDSO

M/s

Page 3 of 8
4. (i) Proof Static test (Permanent set in mm): Sample size- One per lot.
# One in 6 months.

At 181.5 t At 317.5t # Min. Ultimate

Specified Observed Specified Observed Specified Observed
*Knuckle 0.76 - 295 t
Coupler body - 0.76 408 t

* Based on testing with dummy knuckle fixture.

(ii) Proof Static test (Permanent set in mm): Sample size- One per lot.

# One in 6 months.

At 340.20t # Min. Ultimate

Material of yoke- Specified Observed Specified Observed
Grade E steel 0.76 408t

5. Chemical Composition: Sample size- one from each heat.

Heat No.
Body Sl. No.
Qty. Cast
Qty. Offered
Qty. Passed
Qty. Balanced

Quality Control Manager of Inspecting Official of RDSO

M/s

Page 4 of 8
 Chemical Specified Value Observed Value
Analysis
(Max. %) Heat
Grade E 1 2 3 4 5 6 7 8 9 10
C 0.28-0.33
Mn 0.6-0.9
P 0.03(MAX)
S 0.03(MAX)
Si 0.40-0.60
Cr 0.50-0.80
Al 0.020-0.050
Ni 0.50-0.60
Mo 0.15-0.25

6. Microstructure of knuckle: Sample size: One from each heat from Lug.
specified Observed 1 2 3 4 5 6 7 8 9 10
Fine tempered OK/NOT
Marten site OK
7. Hardness: Sample size-5% or min 5 nos.
Grade Specified Observed Value
Value
BHN No. 1 2 3 4 5 6 7 8 9 10
Grade E (Except 241-311
knuckle)

Grade E (For 241-291

Knuckle )

Testing should be done as per ASTM A 370.

8. Impact Test (ASTM A 370): Sample size: One per lot from CBC component.

Specified Observed Value

34.33 J (Min)

Quality Control Manager of Inspecting Official of RDSO

M/s

Page 5 of 8
 9. Nil Ductility Test (ASTM E604 & E208): Sample size: One per lot from CBC Coupler
Except Knuckle.

Specified Observed Value

Value at
57°C

10. Destructive Test: 1 in hundred should be subjected to destructive test as per para
7.2.5 of spec.
Specified Value Observation
1 2
No Blow holes, slag inclusion and
Shrinkage etc. after sectioning.

11. Heat Treatment:

Record of heat treatment to be verified as per OK/ NOT OK
Clouse 5.3.8 of specn.

12. Variation of Weight: 10% of Lot.

Specified Value Observation

Within +5% to -3%

13. Radiographic test (Sample size 10%) - ASTM E446 Level II. Location of radiography
test Should be as per annexure – II of specification WD-70-BD-10.

Quality Control Manager of Inspecting Official of RDSO

M/s

Page 6 of 8
14. Gauge Check: As per RDSO Drawing.
(Sample size-10% or min 10 nos.)
Parameters Gauge No. Observation
WD-84073-S-
COUPLER HEAD 10A Contour Gauge 1-RC
Bottom anticreep 2-RC
Vertical Location
Bottom anticreep 3-RC
Horizontal Location
Top anticreep 4-RC
Vertical Location
Pivot Lug 5-RC
Pin Protector 6-RC
Pulling Lug (Knuckle side) 7-RC
Pivot Pin 8-RC
Lock chamber 9-RC
Lock hole 10-RC
Rotary Lug 11-RC
Shank end pinhole 12-RC
Coupler Shank Shank height 15-RC
Shank butt width 17-RC
Pin hole shank wail 18-RC
thickness
Butt rear wall thickness 19-RC
Pivot pin hole 20-RC
Shank height with Wear 21-RC
Plate
Shank Length (Non 22-RC
transition)
Shank butt end contour 23-RC
Spherical butt and pin hole 24-RC
Shank butt height 25-RC

Quality Control Manager of Inspecting Official of RDSO

M/s

Page 7 of 8
 KNUCKLE Knuckle Bottom Pulling Lug 41-RC
Knuckle Movable Point 42-RC
Knuckle Hub 43-RC
Knuckle Tail Height 44-RC
Knuckle Top Pulling Lug 45-RC
Knuckle Tail Shelf 46-RC
Knuckle Pin Hole 47-RC
Knuckle Length 48-RC

Yoke Mouth opening Y-1

Concentricity Y-2
Head height Y-3
Strap thickness Y-4
Strap width Y-5
Strap outside width Y-6
Pocket height Y-7
Pocket length Y-8
Back height Y-9
Head width (out side) Y-10
Yoke pin hole Y-11

15. Details of in process inspection conducted by inspectors during this Purchase

Inspections (At least one or two in process inspection shall be done)-
Name of process inspection Remarks (Give in details)

Quality Control Manager of Inspecting Official of RDSO

M/s
Page 8 of 8