美国石油协会API7-1(5)

SPECIFICATION FOR ROTARY DRILL STEM ELEMENTS 19

Figure C.2 illustrates the basic models for determining the ER of simple hollow parts and hollow parts with more complicated shapes.

1 23T4T

T Key

T1 round ER = 1.0 T

a

ER = 1.1 T 2 hexagonal a

3 square ER = 1.25 T

a

or plate ER = 1.5 T 4 rectangular

a

when “L” is less than “T”, treat the section as a plate of “L” thickness b

ER = equivalent round

ab

Figure C.1 — Correlation between significant dimensions of simple solid shapes of

length “L” to the diameters of round bars

1 2

TDL

Key 1 2 a b

b

Tube open both ends a ER = 2 T

Tube restricted or closed at one or both ends ER = 2.5 T when D is less than 2.5 inches ER = 3.5 T when D is greater than 2.5 inches

when “L” is less than “D”, treat as a plate of “T” thickness.

when “L” is less than “T”, treat section as a plate of “L” thickness. ER = equivalent round

bDT

TFigure C.2 — Correlation between the significant dimensions of simple hollow parts and hollow parts with more complicated shapes to the diameters of round bars

C.6 Mechanical test requirements

Tensile, hardness and impact specimens shall be removed from sacrificial parts, or prolongations or a QTC after the final heat treatment cycle. When tensile, hardness or impact tests are taken from sacrificial parts or prolongations, the tests shall be at a depth that corresponds to the critical location of the finished part. When a solid QTC is used to verify mechanical properties, the test specimen shall be removed so that the longitudinal axis of the specimens is at a depth equal to or greater than 1/4 T. If a hollow QTC is used, the test specimens shall be removed so that the longitudinal axis of the specimens is located mid-wall of the QTC.

20 ADDENDUM 3 TO ANSI/API SPECIFICATION 7-1/ISO 10424-1

Location of the mid wall from the outside surface of the hollow QTC can be found by the following formula:

Mid-wall = (OD –ID)/4 where

OD is the outside diameter of the QTC

ID is the inside diameter of the QTC at its thickest section

C.6.1 Tensile testing

The standard size 12,5 mm (0.500 in.) diameter round test specimen conforming to the requirements of ISO 6892 or ASTM A370 shall be used for tensile testing, unless the physical configuration prevents their use. If the standard size specimen can not be used, the next smaller sub-sized specimens shall be used. Yield strength shall be determined by tests on cylindrical specimens conforming to the requirements of ISO 6892 or ASTM A370, 0.2% offset method.

C.6.2 Hardness testing

At least one Brinell hardness test shall be performed on the surface of each production part after the final heat treatment cycle. A Brinell hardness test is required on the surface of the QTC if a QTC is used to verify mechanical properties. A Brinell hardness test is also required at the location where the specimens are taken for the tensile and impact tests.

C.6.3 Impact strength testing

Charpy V-notch impact tests shall be conducted at a temperature of 21° C ± 3° C (70° F ± 5° F). Tests conducted at lower temperatures that meet the absorbed energy requirements are acceptable.

The standard size 10 mm × 10 mm(0.394 in. × 0.394 in.) test specimen conforming to the requirements of ISO 6892 or ASTM A370 shall be used for impact testing, unless the physical configuration prevents their use. If the standard size specimen can not be used, the next smaller sub-sized specimens shall be used. If it is necessary to use sub-size impact specimens, the acceptance criteria shall be multiplied by the appropriate adjustment factor listed in Table 2 in Sub clause 5.2.3.3. Sub-size test specimens of width less than 5 mm (0.197 in.) shall not be permitted. One set of 3 specimens shall be tested.

C.6.4 Acceptance criteria for tensile, yield, elongation, impact and hardness

The mechanical properties of the critical section of the part shall comply with the requirements of Table C.1.

Table C.1 — Mechanical properties and tests for heavy section tools

Yield strength

MPa (psi) minimum

Tensile strength

MPa (psi) minimum

Elongation, with Gauge length fourTimes diameter

% minimum

Impact strength

Joules (ft-lbs) Average

3

specimens

54J (40)

Minimum single specimen 47J (37)

277 - 352 Brinell hardness

HBW

689 (100,000) 758 (135,000)

13

SPECIFICATION FOR ROTARY DRILL STEM ELEMENTS 21

In clauses 8.1.7.1.2, 8.1.7.2, 8.1.7.3, and 8.1.7.4; change Spec 7 to Spec 7-2.

In clauses 6.6, 7.6, and 8.1.6; change Clause 10 to Clause 11.

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