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JGJ 18-2012: Specification for welding and acceptance of reinforcing steel bars
JGJ 18-2012
JGJ
INDUSTRY STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC
Record No.: J 253-2012
P JGJ 18-2012
Specification for Welding and Acceptance of
Reinforcing Steel Bars
ISSUED ON: MARCH 01, 2012
IMPLEMENTED ON: AUGUST 01, 2012
Issued by: Ministry of Housing and Urban-Rural Development of the
People’s Republic of China
INDUSTRY STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
Specification for Welding and Acceptance of
Reinforcing Steel Bars
Approved by: Ministry of Housing and Urban-Rural Development of the People’s
Republic of China
IMPLEMENTED ON: AUGUST 01, 2012
2012 Beijing
Table of Contents
Foreword ... 6
1 General Provisions ... 8
2 Terms and Symbols ... 8
2.1 Terms... 8
2.2 Symbols ... 11
3 Materials ... 14
4 Welding of Reinforcing Steel Bar ... 16
4.1 Basic provisions ... 16
4.2 Resistance spot welding of reinforcing steel bar ... 21
4.3 Flash butt welding of reinforcing steel bar ... 22
4.4 Flash butt welding of stirrup ... 25
4.5 Arc welding of reinforcing steel bar ... 27
4.6 Electroslag pressure welding of reinforcing steel bar ... 33
4.7 Gas pressure welding of reinforcing steel bar ... 36
4.8 Submerged-arc pressure welding of reinforcing steel bar at prefabricated
components ... 38
4.9 Submerged-arc stud welding of reinforcing steel bar at prefabricated
components ... 40
5 Quality Inspection and Acceptance ... 42
5.1 General requirements ... 42
5.2 Welded frame and welded fabric of reinforcing steel bar ... 46
5.3 Flash butt welded joint of reinforcing steel bar ... 48
5.4 Flash butt welded joint of stirrup ... 49
5.5 Arc welded joint of reinforcing steel bar ... 49
5.6 Electroslag pressure welded joint of reinforcing steel bar ... 51
5.7 Gas pressure welded joint of reinforcing steel bar ... 52
5.8 T-joint of reinforcing steel bar at prefabricated components ... 53
6 Examination of Weldor ... 55
7 Welding Safety ... 59
Appendix A Quality Acceptance Record of Welded Joints Inspection Group of
Reinforcing Steel Bar ... 62
Appendix B The Certificate of Weldor Examination for Reinforcing Steel Bar 69
Explanation of Wording in This Specification ... 72
List of Quoted Standards ... 73
Specification for Welding and Acceptance of
Reinforcing Steel Bars
1 General Provisions
1.0.1 This Specification was formulated with a view to adopting reasonable welding
procedure and unified quality acceptance criteria, achieving construction safety,
guaranteeing quality, advanced technology, material and energy conservation in the
welding procedure of reinforcing steel bars.
1.0.2 This Specification is applicable to welding procedure of reinforcing steel bars and
the quality inspection and acceptance in generally industrial and civil construction
engineering concrete structure.
1.0.3 Welding procedure of reinforcing steel bar and the quality inspection and
acceptance shall not only be carried out according to this Specification, but also comply
with the provisions of relevant current national standards.
2 Terms and Symbols
2.1 Terms
2.1.1 Hot rolled plain bars
Finished reinforcing steel bar that is formed by hot rolling, generally with circular cross
section and smooth surface.
2.1.2 Hot rolled bars
Reinforcing steel bar that is delivered according to hot-rolled state, whose
metallographic structures are mainly ferrite and pearlite and shall be free from other
microstructures (such as tempered martensite microstructure on base circle) with
influence on service performance.
2.1.3 Hot rolled bars of fine grains
Reinforcing steel bar of fine grains that is formed through controlled rolling and cooling
process in the hot-rolled process, whose metallographic structures are mainly ferrite
and pearlite and shall be free from other microstructures (such as tempered martensite
microstructure on base circle) with influence on service performance; their grain size
A kind of fusion welding method that welding wire is regarded as one electrode and
reinforcing steel bar as another electrode; and carbon dioxide gas is regarded as arc
medium to protect metal drop, welding pool and hot metal in weld zone. Carbon-dioxide
arc welding is hereinafter referred to as CO2 welding.
2.1.12 Electroslag pressure welding of reinforcing steel bar
A kind of pressure welding method that two pieces of reinforcing steel bars are placed
in vertical butting form; by direct or indirect arc initiation method, in utilization of welding
current and through clearance between end faces of the reinforcing steel bars; arc
process and electroslag process are formed below flux layer to generate arc heat and
resistance heat so as to melt the reinforcing steel bars and complete the pressurization.
2.1.13 Gas pressure welding of reinforcing steel bar
A kind of pressure welding method that oxyacetylene or oxygen-liquefied petroleum
gas flame (or other flames) is adopted to heat the joint of the two reinforcing steel bars
so as to make them reach thermoplastic state (solid-state) or melted state; then
complete the pressurization.
2.1.14 Submerged-arc pressure welding of reinforcing steel bar at prefabricated
components
A kind of pressure welding method that reinforcing steel bar and steel plates are placed
in the form of T-shaped joint to generate arc below the flux layer in utilization of welding
current, form molten pool and complete pressurization.
2.1.15 Submerged-arc stud welding of reinforcing steel bar at prefabricated
components
A kind of welding method that reinforcing steel bars are inserted into the molten pool
at the right time to form a T-shaped joint after arc stud welding gun is used to clamp
reinforcing steel bars so as to make the reinforcing steel bars vertically aligned with
steel plates and stud welding power equipment is adopted to generate high current
and welding arc in a short time so as to generate molten pool between end faces of
welding of reinforcing steel bars and steel plates under the protection of flux layer.
2.1.16 Waiting weld stirrup
Semi-finished stirrup that the aligned reinforcing steel bars are adopted to make shape
specified in the design according to inner clear dimension and angle of stirrup and are
waiting for flash butt welding.
2.1.17 Butt welded stirrup
Closed-loop stirrup that is formed through flash butt welding of waiting weld stirrup.
F – HRBF500 hot-rolled ribbed bar of fine grains.
2.2.2 Dimension and symbols for welded joints of reinforcing steel bar
αg - the inside clear length of stirrup;
b - the width of weld surface;
bg - the inner clear width of stirrup;
bh - the temper bead;
br - the contour weld bead;
d - the diameter of reinforcing steel bar (stirrup);
dy - the pressed depth;
fy - the pressure weld surface;
hy - the excess weld metal;
K - the dimension of weld leg;
l - the length of auxiliary rod and overlap length;
Lg - the blanking length of stirrup;
S - the effective thickness of weld.
2.2.3 Symbols of welding procedures
A - the burn-off allowance;
α1 - the left burn-off allowance;
α2 - the right burn-off allowance;
A1 - the primary burn-off allowance;
α1.1 - the left primary burn-off allowance;
α2.1 - the right primary burn-off allowance;
A2 - the secondary burn-off allowance;
α1.2 - the left secondary burn-off allowance;
α2.2 - the right secondary burn-off allowance;
t3.2 - the upset current-off time;
△ - the total welding allowance. ...