JB/T 5000.9-2007 PDF in English
JB/T 5000.9-2007 (JB/T5000.9-2007, JBT 5000.9-2007, JBT5000.9-2007)
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| JB/T 5000.9-2007 | English | 260 |
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Heavy mechanical general techniques and standards. Part 9: Cutting
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| JB/T 5000.9-1998 | English | 359 |
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The heavy mechanical general techniques and standards. Cutting
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Standards related to (historical): JB/T 5000.9-2007
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JB/T 5000.9-2007: PDF in English (JBT 5000.9-2007) JB/T 5000.9-2007
JB
MECHANICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 25.120.20
H 90
Filing No.: 21703-2007
Replacing JB/T 5000.9-1998
Heavy Mechanical General Techniques and Standards –
Part 9: Cutting
ISSUED ON: AUGUST 28, 2007
IMPLEMENTED ON: FEBRUARY 1, 2008
Issued by: National Development and Reform Commission of the People's
Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 General Requirements ... 5
4 Tolerance without Indication ... 7
4.1 Length Dimension, Rounding Radius and Chamfering Height, Angular Dimension 7
4.2 Tolerance of Form and Position ... 10
5 Unnoted Tolerance for Symmetry of Key Groove ... 12
6 Positional Tolerancing without Indication of Threaded Hole and Unthreaded Hole
... 12
7 Thread ... 14
8 Center Hole ... 14
9 Unnoted Surface Roughness ... 14
10 Requirements for Allowed Machining According to Shape of Cutter ... 15
11 Rolling ... 17
11.1 Methods and Purpose for Rolling ... 17
11.2 Preparation for Rolling... 17
11.3 Rolled Surface ... 17
Heavy Mechanical General Techniques and Standards –
Part 9: Cutting
1 Scope
This part of JB/T 5000 specifies general requirements of cutting and tolerance without
indication; and specific requirements on key groove, hole diameter and hole distance, center
hole, tolerance without indication and allowed shape of cutter, etc.
This part is applicable to cutting of heavy machinery product parts.
All the product drawings and technical documents, if without special requirements, shall meet
the requirements of this part.
2 Normative References
The following documents contain provisions which, through reference in this text, constitute
provisions of this part. For dated references, subsequent amendments to (excluding
corrigendum), or revisions of, any of these publications do not apply. However, parties to
agreements based on this standard are encouraged to investigate the possibility of applying
the most recent editions of the standards. For undated references, the latest edition applies.
GB/T 3 Run-outs, Undercuts and Chamfers for General Purpose Metric Screw
Threads (GB/T 3-1997, eqv ISO 3508:1976, ISO 4755: 1983)
GB/T 197-2003 General Purpose Metric Screw Threads - Tolerances (ISO 965-1: 1998,
MOD)
GB/T 1184-1996 Geometrical Tolerance - Geometrical Tolerances for Features without
Individual Tolerance Indications (eqv ISO 2768-2: 1989)
GB/T 1804-2000 General Tolerances - Tolerances for Linear and Angular Dimensions
without Individual Tolerance Indication (eqv ISO 2768-1:1989)
GB/T 5277-1985 Fasteners; Clearance Holes for Bolts and Screws (eqv ISO 273:1979)
3 General Requirements
3.1 The parts after machining shall meet the requirements of product drawing and technical
document as well as this part.
3.2 Parts shall be subjected to inspection and acceptance according to procedures, and next
procedure can start only after the previous procedure is qualified.
3.5 Parts after fine machining is not allowed to be placed directly on the ground, and
necessary support and protective measures shall be taken. The machined surface shall be free
from rust as well as bumping, scratching and other defects that affect property, service life or
appearance.
3.6 The fitting surface, friction surface, locating surface and other working surfaces after
fine machining is not allowed to be with stamped with mark.
3.7 As for parts whose final procedure is heat treatment, after heat treatment, their surfaces
shall be free from oxide skin after heat treatment. Fitting surface and tooth surface after fine
machining shall be free from annealing, bluing, discoloration, etc.
4 Tolerance without Indication
4.1 Length Dimension, Rounding Radius and Chamfering Height, Angular
Dimension
4.1.1 Applicable Objects:
Size without tolerance indication between two cutting surfaces (size without tolerance
indication of parts that are cut short through sawing shall be specified separately).
Size without tolerance indication is applicable to:
-- Length dimension, such as external dimension, internal dimension, step dimension,
diameter and distance dimension.
-- Rounding radius and chamfering height.
-- Angular dimension, including dimension with angle indication and without angle
indication, such as the angles of regular polygon.
-- Machining length and angular dimension of parts that are combined together.
Size without tolerance indication is not applicable to:
-- Auxiliary dimension in brackets.
4.2.3.2 Roundness, Cylindricity, Line Profile and Surface Profile
Form tolerances are limited by the dimensional tolerance range; unnoted tolerance of
roundness, cylindricity, line profile and surface profile shall be less than the value of its
unnoted dimensional tolerance.
4.2.4 Tolerance of Position
4.2.4.1 Tolerance of Parallelism
The straightness (flatness) of two parallel elements and the unnoted tolerance of size for their
distance, whichever is larger shall be taken as the unnoted tolerance of parallelism. The
unnoted tolerance of straightness (flatness) shall be subject to that of the longer one in the
elements.
4.2.4.2 Tolerance of Perpendicularity
Unnoted tolerance of perpendicularity shall be in accordance with those specified in Table 7.
4.2.4.3 Tolerance of Inclination
Unnoted tolerance of inclination shall be in accordance with those specified in Table 5.
4.2.4.4 Tolerance of Symmetry
Unnoted tolerance of symmetry of non-rotating symmetry elements shall be in accordance
with those specified in Table 8. Unnoted tolerance also applies if one of symmetry elements is
rotating symmetry and another is non-rotating symmetry (such as, axle head and sleeve of
universal shaft).
4.2.4.5 Tolerances of Coaxiality and Circular Run-out
Unnoted tolerance of coaxiality and circular run-out (radial direction, end surface and
diagonal direction) shall be in accordance with those specified in Table 9.
5 Unnoted Tolerance for Symmetry of Key Groove
Unnoted tolerance for symmetry of key groove shall be in accordance with those specified in
Table 10.
6 Positional Tolerancing without Indication of Threaded
Hole and Unthreaded Hole
Table 11 is applicable to the threaded hole and unthreaded hole connected with bolt or screw;
hole diameter of unthreaded hole shall be given according to the moderate mounting
dimension specified in GB/T 5277-1985; for positional tolerancing of coarse fit unthreaded
hole, refer to this requirement.
Indication of positional tolerancing is excluded from accumulation of error. It means that each
hole distance is the theoretical and correct coordinate dimension without deviation. Positional
tolerancing without indication for cylinder of threaded hole and unthreaded hole shall be in
accordance with these specified in Table 11.
7 Thread
7.1 Regular thread accuracy shall be in accordance with 6H/6g specified in GB/T 197-2003.
7.2 Size of run-outs, undercuts and chamfers for general-purpose metric screw threads shall
be in accordance with the requirements of GB/T 3.
7.3 The machined thread surface shall be free from casting skin, bumping, chasing, burr and
other defects.
7.4 Before machining of thread, threading-in side of male and female thread must be
chamfered, by 45° for male threads; by 60° for female threads. The depth of chamfer is equal
to the height of teeth pattern.
7.5 Surface roughness of general-purpose metric screw threads shall not be greater than Ra
12.5μm for female threads or Ra 6.3μm for male threads.
8 Center Hole
8.1 It shall be indicated clearly that the center hole needs be reserved or removed in the
drawing; otherwise it shall be considered that reservation or removal of center hole is
allowed.
8.2 Types and size of center hole shall be subject to corresponding standard.
8.3 Surface roughness on conical surface of center hole: when used for rough machining, Ra
value shall be not greater than 6.3μm; when used for fine machining, Ra value shall be not
greater than 3.2μm; when used for processing of precision component, Ra value shall be not
greater than 1.6μm.
9 Unnoted Surface Roughness
Surface roughness not indicated in the drawing shall be in accordance with the requirements
in Table 12.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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