Transcript Attachment 4 API 6A718 Plenary

API6A718 Work Group Update
February 6, 2014
API6A718 Work Group Meeting
January 30, 2014
Brinell to Rockwell Conversion
Current API6A718
Current Draft - Oct. 8, 2013
Situation
• Industry experience along with data
provided by Foroni, Carpenter, VDM and
Bohler demonstrates that Table 3 of ASTM
E140 is inaccurate for the alloys of
interest.
HBW vs HRC for PH Nickel Alloys
430
410
HBW
390
370
350
Foroni
CTC
VDM
Bohler
E140
330
310
290
32
33
34
35
36
37
38
Rockwell C
39
40
41
42
43
MR0175 provides HRC limits and permits
users to establish conversion tables.
Part 3, para. 6.2.1
“The conversion of hardness readings
to or from other scales is materialdependent. The user may establish the
required conversion tables.”
ASTM E10 & E18
“conversions are, at best, approximations
and, therefore, should be avoided except for
special cases where a reliable basis for the
approximate conversion has been obtained
by comparison tests.”
ASTM E140
Table 3 - “intended to apply particularly to
the following: nickel-aluminum-silicon
specimens”
Note 1 - “most of the values were generated
using a steel ball while the tungsten carbide
balls used today will produce different
values.”
Conversion formula and table generated
from Foroni and Carpenter data
API CSOEM meeting on Friday 24 January
2013, Sterling Lewis, the Chairman of API
SC6, submitted a funding proposal for the
round robin tests necessary to develop the
data required for two ASTM hardness
correlations. These two hardness
correlations will cover Nickel-ChromiumMolybdenum alloys and low carbon
martensitic stainless steels.
Proposals
A.Ballot 6A718 with Brinell values from ASTM
E140 table 3
B.Ballot 6A718 without Brinell requirements for the
additional alloys. Allow users to establish tables
in accordance with MR0175
• Revisit once ASTM has established table for
Nickel-Chromium-Molybdenum alloys
Resolution by unanimous vote was to eliminate HBW values until an
appropriate conversion table can be developed in conjunction with ASTM
UNS number
Material
Designation
Minimum
Hardness a
HRC (HBW)
Maximum
Hardness b
HRC (HBW)
120K
32 (--d)
43 (--d)c
140K
34 (--d)
43 (--d)c
120K
32 ()
40 ()
140K
32 ()
40 ()
N07725
120K
32 (--d)
43 (--d)c
N09925
110K
26 (--d)
38 (--d)c
N09935
110K
24 (--d)
34 (--d)c
N09945
125K
32 (--d)
42 (--d)c
N07716
N07718
140K
34 ((--d)
42 (--d)c
d - The conversion of hardness readings to or from other scales is materialdependent. Conversion tables maybe used upon agreement between purchaser,
manufacturer and end user..
Hardness Testing Frequency
Current API6A718
• Each piece of production material and each QTC shall
be hardness tested on or near the surface using the
Brinell (10 mm ball, 3000 kgf) method per ASTM E 10 or
the Rockwell C method per ASTM E 18 after the final
heat treatment cycle. Each piece of production material
and each QTC shall have a minimum of one hardness
test.
MR0175 section 6.2
If hardness measurements on parent metal are specified,
sufficient hardness tests shall be made to establish the
actual hardness of the CRA or other alloy being examined.
Individual HRC readings exceeding the value permitted by
this part of ISO 15156 may be considered acceptable if the
average of several readings taken within close proximity
does not exceed the value permitted by this part of ISO
15166 and no individual reading is greater than 2 HRC
above the specified value. Equivalent requirements shall
apply to other methods of hardness measurement when
specified in this part of ISO 15156 or referenced in a
manufacturing specification.
Current Draft - Oct. 8, 2013
a.
Each piece of production material shall be hardness tested on or
near the surface using the Rockwell C method per ASTM E 18 or the
Brinell (10 mm ball, 3000 kgf) method per ASTM E 10 after the final
heat treatment cycle. For Rockwell C-scale testing three adjacent
indentations shall be made and the mean hardness reported. No
individual hardness number may be greater than 2 HRC units
above the maximum specified hardness number. For Brinell
testing at least one indentation shall be made. In case of dispute,
the Rockwell C-scale method shall be the referee method.
b.Cross-section hardness testing shall be performed on each QTC
using the Rockwell C method per ASTM E 18 Three adjacent
indentations shall be made near the surface, three adjacent
indentations shall be made at ¼ thickness and three adjacent
indentations at the center. The mean hardness at each location
shall be reported. No individual hardness number may be
greater than 2 HRC units above the maximum specified
hardness number.
c. Rounding of test results to determine conformance to
specification shall be in accordance with ASTM E29
Agreed upon resolution is to only require one Brinell test per piece and
include the wording below in red
a.
Each piece of production material shall be hardness tested
on or near the surface using the Rockwell C method per
ASTM E 18 or the Brinell (10 mm ball, 3000 kgf) method per
ASTM E 10 after the final heat treatment cycle. For
Rockwell C-scale testing three adjacent indentations shall
be made and the mean hardness reported. No individual
hardness number may be greater than 2 HRC units above
the maximum specified hardness number. For Brinell
testing one indentation is sufficient. If the results do
not satisfy the applicable requirements, additional
adjacent Brinell tests may be taken and all additional
indentations shall meet. In case of dispute, the
Rockwell C-scale method shall be the referee method
Reporting of Hardness Values
Agreed upon resolution is
For each piece of production material the mean value of surface
hardness test shall be reported. All hardness indentations taken on
QTC shall be reported.