Weld Construction

Welding Preparation

In Welding work plan should be first to do a Construction made, how to make, how the use of equipment / construction, the things that may occur with the construction. To obtain a construction joint is good and true, then several things need to be as follows:
1. Welding Procedure Specification (WPS) and Procedure Qualification Record (PQR).
2. Human factors
3. The Machine
4. Las standard equipment in accordance
5. Material (material) and the weld wire (electrode)
6. Environment.

Welding Procedure Specification (WPS) and Procedure Qualification Record (PQR).
a. Welding Procedure Specification (WPS)
Before production begins las, specifications detail the procedures that must be created and qualification welded to demonstrate that the mechanical nature of the appropriate (strength, ductility and violence) and the welded/ free from defects can be made through the procedure. Quality welded must be tested with the non-destructive and destructive. Procedures must be obeyed, except when there are changes that are desired by a specific company (in particular the variables essential)
b. Procedure Qualification Record (PQR)
Every detail and procedure that must be qualification Record and should be complete viewing results to qualification procedure. Records must be maintained during the procedure is still used.


Human factors.
Interpreter service and the joint will be to handle the implementation of joint construction work, before carrying out construction works weld, need to test with the WPS that has been tested and passed with a similar material that will be used in the construction joint. Testing and interpreter service, commonly called las welder performance test (WPT).
During the process of implementation of the test operator and weld interpreter, experts and inspection of all parties concerned with a construction joint is present and witnesses, including experts from government inspection authorities. After the test is declared passed, then the interpreter weld service and are given a certificate of test weld or welding operator / welder certificate by government authorities. fabricator next party or the equipment that employ weld interpretersor operator is permitted to create weld construction accordance WPS that has been set. Welding in the process of examination is very important to obtain quality results in accordance with weld standard that have been defined.construction phases weld inspections, the first examination before welding process, both during the examination elding process, after the third weld examination.

Welding preparation machine
Welding machine is a source of energy (heat) in the weld process. For the construction weld machine needs to be matched with the weld process used. In the case of weld construction, weld machine that is used depends on the weld process used. Polarity machine consists of weld machine AC or DC (DCEP / DCEN) with a capacity of 30 ampere - 500 ampere.

Preparation Tools.
No equipment is good and will lead to complete not only the weld results not perfect, can even lead to things worse such as accidents, fire / explosion, electrical that can harm workers or other people. Avoid for things that do not want to work before then pwelding needs to be done a few things, namely:

a. Tool Safety:
- Preparation protective clothing
- Gloves
- Safety glass
- Apron
- Safety-shoes

b. Additional Tools:
- Chipping hammer
- brush wire
- Carved cuneiform
- grinder hands
- Pinchpenny rough
c. Measure Tool:
- The length of
- The level
- Welding gauge.

Material
Material / material that is prepared:
a. Preparing the work objects, work objects must be clean and rust, oil, fat or other substances contamination, in order to avoid the occurrence of porosity on the welding results . Materials used in the joint work should be prepared and reviewed by supervisors and welding by welding inspector.
b. The selection of add (pole)
Add or electrode material in the shielded metal arc welding (SMAW) in addition to functioning as a material also functions as a bow menghasikan power (electrode). Weld wire used in the welding process, strength at least equal to the material strength will through.

Connection preparation
a. Connection weld preparation.
Make sure the connection surface cleanliness must be flat and free from dirt, there is no oil, fat or other chemical substances terkontaminasi. Do not touch the surface is clean by hand or with objects that can cause contamination, if permitted to use clean cloth.

b. Setting machine las
- The las: SMAW
- polarity electrode positive (DCEP)
- Large flow: 70 - 140 amp (as needed)

c. Sketch material and tack Weld
Put the snippet in the pipe work table with the surface at the top of the dibevel, ltake wire V-shaped spacer that Bevel pipe above the surface (size of wire spacer 2.4 s / d 3.2 mm).

Put part pipe above the second wire on the pipe spacer ago Align the first and second-level connection with the water-pipe to pass a connection into the straight and perfect. Make tack along Weld 10 mm s / d 15 mm between the two connection pipes by using a filler rod strength stronger pull from the base-metal. Tack Weld must permeate the perfect connection between the two pipes. High penetration weld can not be more than 1.6 mm.

Shift the wire on the end of the spacer and do Bevel Weld tack of making the second If there is a root of the wide gap side, then do the making of the third tack Weld. Tack due to pulling out of Weld, the distance at the gap that will be the same gap

Making do tack on Weld pipes with the length and the same distance. Making a connection with the preparation las perfectly welding facilitate the implementation of the weld quality is good. (Before starting the preparation pengelasan joint review by supervisor / welding supervisor or inspektor).
Welding Procedure Specification (WPS): - Example
Weld Procedure Number 30 P1 TIG A Issue 01
Qualifying Welding Procedure (WPAR) WP T17 / A

Manufacturer: National Fabs Ltd
25 Lane End
Birkenshaw
Leeds

Location: Workshop

Welding Process: Manual TIG
Joint Type: Single sided Butt Weld
Method Of Preparation
and Cleaning: Machine and Degrease
Parent Metal Specification: Grade 304L Stainless Steel
Parent Metal Thickness 3 to 8mm Wall
Pipe Outside Diameter 25 to 100mm
Welding Position: All Positions
Welding Progression: upwards

Joint Design Welding sequences

Run Process Of Size
Metal filler Current
A Voltage
Type Of V
Current / Polarity Wire Feed
Travel Speed
Speed Heat Input
1
2 And Subs TIG
TIG 1.2mm
1.6mm 70 - 90
80 - 140 N / A DC -
DC-N / A N / A N / A

Welding Consumables: --
Type, Designation Trade Name:
Any Special Baking or drying:
Gas flux:
Gas Flow Rate - Shield:
- Backing:
Tungsten Electrode Type / Size:
Details of Back Gouging / Backing:
Preheat Temperature:
Interpass temperature:
Post Weld Heat Treatment
Time, temperature, method:
Heating and Cooling Rates *:

BS 2901 Part 2: 308S92
No
Argon 99.99% Purity
8 - 12 LPM
5 LPM
2% Thoriated 2.4mm Dia
Backing Gas
Min 5 ° C
200 ° C Max
Not Required
Production Sequence

1. Clean Weld 25mm and borders to bright metal using approved solvent.
2. Position items to be welded Ensuring good fit up and apply purge
3. Tack Weld parts together using TIG, tacks to at least 5mm min length
4. Deposit root run using 1.2mm dia. wire.
5. Inspect the root run Internally
6. Complete Weld using 1.6mm dia wire using Stringer Beads as required.
7. 100% Visual inspection of completed Weld