TB/T 1632.4-2014 English PDF (TBT1632.4-2014)

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TB/T 1632.4-2014: Welding of rails - Part 4: Gas pressure welding
TB/T 1632.4-2014
TB
RAILWAY INDUSTRY STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
ICS 45.120
S 17
Replacing TB/T 1632.4-2005
Welding of rails - Part 4. Gas pressure welding
ISSUED ON. OCTOBER 30, 2014
IMPLEMENTED ON. MAY 1, 2015
Issued by. National Railway Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Requirements ... 5 
4 Inspection methods ... 11 
5 Inspection rules ... 14 
Annex A (Informative) Gas pressure welding records of rails ... 19 
Annex B (Normative) Records of weld fracture defects ... 20 
Foreword
TB/T 1632 Welding of rails is divided into four parts.
— Part 1. General specification;
— Part 2. Flash butt welding;
— Part 3. Thermit welding;
— Part 4. Gas pressure welding.
This Part is Part 4 of TB/T 1632.
This Part was drafted in accordance with the provisions given in GB/T 1.1-2009.
This Part replaces TB/T 1632.4-2005 Welding of rails - Part 4. Gas pressure
welding. Compared with TB/T 1632.4-2005, the major technical changes are as
follows.
— MODIFY the equipment requirements for gas pressure welding (SEE 3.2
in this edition and 3.2 in 2005 edition);
— MODIFY the personnel requirements for gas pressure welding (SEE 3.3
in this edition and 3.3 in 2005 edition);
— MODIFY the process requirements (SEE 3.4 in this edition and 3.4 in
2005 edition);
— ADD the requirements for macroscopic inspection items; ADD the
requirements for 1 080MPa rail welded joints (SEE 3.5 in this edition and
3.5 in 2005 edition);
— MODIFY the requirements for hardness of welded joints (SEE 3.5 in this
edition and 3.5 in 2005 edition);
— MODIFY the inspection method (SEE Chapter 4 in this edition and
Chapter 4 in 2005 edition);
— MODIFY the inspection rules (SEE Chapter 5 in this edition and Chapter
5 in 2005 edition);
— MODIFY the Annex A, Gas pressure welding records of rails (SEE Annex
A in this edition and Annex A in 2005 edition);
— MODIFY the Annex B, Records of weld fracture defects (SEE Annex B in
this edition).
Welding of rails - Part 4. Gas pressure welding
1 Scope
This Part of TB/T 1632 specifies the requirements, inspection methods and
inspection rules for the gas pressure welding of rails.
This Part is applicable to the gas pressure welding of 50 kg/m ~ 75 kg/m new
rails.
2 Normative references
The following documents are essential to the application of this document. For
dated references, only the editions with the dates indicated are applicable to
this document. For undated references, only the latest editions (including all the
amendments) are applicable to this document.
GB/T 230.1-2009 Metallic materials - Rockwell hardness test - Part 1. Test
method (scales A, B, C, D, E, F, G, H, K, N, T)
GB/T 231.1-2009 Metallic materials - Brinell hardness test - Part 1. Test
method
GB/T 4340.1-2009 Metallic materials - Vickers hardness test - Part 1. Test
method
GB/T 6394 Metal - Methods for estimating the average grain size
GB/T 8170 Rules of rounding off for numerical values and expression and
judgement of limiting values
GB/T 13298 Inspection methods of microstructure for metals
TB/T 1632.1-2014 Welding of rails - Part 1. General specification
3 Requirements
3.1 Welding rail requirements
The rails for gas pressure welding shall meet the requirements of Chapter 4 in
TB/T 1632.1-2014.
3.2 Equipment and material requirements
3.2.1 Automated gas pressure welding equipment shall be adopted in
preference. In the welding process, it shall be able to automatically record the
change of parameters such as gas flow, rail-end pressure, etc. over time.
3.2.2 The purity of oxygen used for gas pressure welding of rails shall not be
less than 99.5%, while the purity of acetylene shall not be less than 98%.
3.3 Personnel requirements
Each welding operator shall hold a job training certificate issued by the technical
institution approved by the railway authority.
3.4 Process requirements
3.4.1 Welding environment requirements. The welding places shall have no
rain or heavy fog, at a temperature of not lower than 0°C. When the temperature
is below 0°C, measures of heat preservation shall be taken for the oxygen and
acetylene cylinders. Meanwhile, early drying shall be carried out within the
range of 400mm on each end face of the rails to be welded. Wind shall not be
greater than Level 5. In case of above Level 4, wind shielding measures shall
be taken.
3.4.2 POLISH the end faces of rails prior to welding. The allowable deviation
of the end face inclination shall be 0.2mm. SEE Figure 1.
3.4.3 For the alignment clamping operation of rails, alignment shall be based
on the working edges on the top of the rail and the side of the railhead.
3.4.4 The flame surface of the heater shall be parallel to the end face of the
rail.
3.4.5 The convex shearing process shall be carried out automatically. The
convex shearing process shall not cause damage to the joints and the rail
parent metal. After convex shearing, there shall be no macroscopic cracks on
or welding slag squeezed into the surfaces. The maximum convex shearing
allowance (the height of weld reinforcement after convex shearing) for each
part of the joint is as follows. 2mm for railhead; 2.5mm for railhead jaw; 2mm
for rail web; 1.5mm for rail flange.
reinforcement of the rail flange shall be under smooth transition. Longitudinal
grinding shall be carried out along the rails. It is not allowed to carry out
horizontal grinding. There shall be no grinding burn on the rail surfaces.
Misalignment in the vertical and horizontal directions on the non-working faces
of the welded joints shall be conducted with longitudinal grinding transition.
3.4.10 An imitation-type grinding machine shall be used to perform shape
finishing on the top surfaces of the rails and the working edges on the sides of
the railheads for the welded joints. Shape finishing shall maintain the contour
shape of railheads. The length of the shape finishing shall not exceed the limit
of 400mm on both sides of the weld center line. Shape finishing shall not cause
any mechanical or thermal damages to the welded joints or rails. Shape
finishing shall not be used correct the excessive flatness deviation and
excessive joint misalignment.
3.4.11 When a mobile gas pressure welding machine is used for CWR
(continuous welded rail) long rail welding, it shall be operated in coordination
with the CWR laying process. During locking welding, dwell convex shearing
shall be adopted. When the welded joints are cooled to below 300°C, it is
allowed to remove dwell pressure.
3.4.12 Mass production shall be carried out after passing the type inspection.
The production process shall be the same as the test specimens of the type
inspection.
3.4.13 The welded joints (finished products) of each rail shall be marked. The
markings shall be located on the same side of rail web of the welded long rails,
1m to 3m away from the welds. In addition, the markings shall be clear, upright
and identifiable for at least 5 years (or 1 overhaul cycle). The marking method
shall ensure that the welded joints (finished products) of each rail are traceable
based on the record sheet.
3.4.14 After welding, the following information shall be recorded (REFER to
Annex A).
a) rail markings, laying positions and welded joint markings;
b) environmental conditions (i...