PROGRESSIVE SAMPLING

INSPECTION AND EXAMINATION

FLUID SERVICE

It is a general term concerning the application
of a piping system, considering the combination of
fluid properties, operating conditions, and other factors
which establish the basis for design of the piping system



(a) Category D Fluid Service: a fluid service in
which all the following apply:

(1) the fluid handled is nonflammable, nontoxic,
and not damaging to human tissues

(2) the design gauge pressure does not exceed 1035
kPA (150 psi);

(3) the design temperature is from −29°C (−20°F)
through 186°C (366°F).

(b) Category M Fluid Service:

it is a  fluid service inwhich the potential for personnel
exposure is judgedto be significant and in which a single
exposure to a very small quantity of a toxic fluid, caused
by leakage,can produce serious irreversible harm to persons on
breathing or bodily contact, even when prompt restorative
measures are taken.


(d) Normal Fluid Service: a fluid service pertaining
to most piping covered by this Code, i.e., not subject
to the rules for Category D, Category M, or High
Pressure Fluid Service

NOTE:-

High pressure is considered herein to be pressure
in excess of that allowed by theASME B16.5 code
PN 420 (Class 2500) rating for the specified design
temperature and material group. However,there are
no specified pressure limitations for the application
of these rules.

LIMITATIONS

 This Code excludes the following:

(a) piping systems designed for internal gauge pressures
at or above zero but less than 105 kPa (15 psi),
provided the fluid handled is nonflammable, nontoxic,
and not damaging to human tissue as defined in 31.3,
and its design temperature is from −29°C (−20°F)
through 186°C (366°F);

(b) power boilers in accordance with B&PV Code2
Section I and boiler external piping which is required
to conform to B31.1;

(c) tubes, tube headers, crossovers, and manifolds
of fired heaters, which are internal to the heater enclosure;
and

(d) pressure vessels, heat exchangers, pumps, compressors,
and other fluid handling or processing equipment,
including internal piping and connections for
external piping.

ASME B31.3 SCOPE

Rules for the Process Piping Code Section B31.3

It has been developed considering piping typically found
in petroleum refineries; chemical, pharmaceutical, textile,
paper, semiconductor, and cryogenic plants; and
related processing plants and terminals.

300.1.1 Content and Coverage

(a) This Code prescribes requirements for materials
and components, design, fabrication, assembly, erection,
examination, inspection, and testing of piping.

(b) This Code applies to piping for all fluids, including:

(1) raw, intermediate, and finished chemicals;
(2) petroleum products;
(3) gas, steam, air, and water;
(4) fluidized solids;
(5) refrigerants; and
(6) cryogenic fluids.

ASME B31.3

AMERICAN SOCIETY OF MECHANICAL ENGINEERS

WELDER PERFORMANCE QUALIFICATION - PART 6

Test Coupon Preparation for the Destructive Bend Test

Test Coupon Marking and Cutting

It is now the next day since taking the test and the plate has had more than enough time to cool
The first thing is to put a mark in the center of the plate with soap stone. Then you need to put a mark one inch above it and one inch below it. Then the next marks are 1½ inches above the top mark and again 1½ inches below the bottom mark. The two outside marks are the bend specimens. Using a square I marked lines across the test plate as to where they will be cut. In the case of coupon failure the middle of the plate can be used as a backup coupon, as long as the failure of the bend falls within the ASME acceptance criteria for a bend test. Next my initials are inscribed, and bend test specimens are marked, one for a root bend, the second for a face bend, and the third for an alternate. Just as a not the bend test specimens must be a minimum of 1 1/2 inches wide.
Once I marked the cut lines, I cut them with a horizontal band saw.

WELDER PERFORMANCE QUALIFICATION - PART 5

Testing Requirements

Test requirements for groove welds QW452 consists of either:

One face bend and one root bend except for welding positions 5G & 6G which require 4 bends (Ref QW452.1 Note 4). If the plate exceeds 3/8" side bends may be used.  See QW 466 for precise details and exceptions.

• Note: Bend Tests can in most cases be replaced by Radiography (See Below).
  
  
• Radiography is optional and must be supplemented by bend tests when using GMAW (MIG/MAG) with dip transfer (Short Circuiting Arc) or when welding some special materials. Ref. QW304.
  
  Note: Ultrasonic Examination in lieu of Radiography is not permitted

Test requirements for fillet welds in plate ref. QW452.5:

• One macro section (QW 184) and One fracture test (QW182).

The location where each specimen has to be taken is defined in QW463

Radiography Ref QW 191

• A length of at least 6" must be examined for plate or the entire circumference for pipe.
• If the pipe circumference is less than 6" then more samples must be welded up to a maximum of 4. Ref QW 302.2.

Visual Examination Ref QW 302.2 & QW 190
Performance test coupons must show complete joint penetration with full fusion of the weld metal and base metal. The welder performance test must follow a properly qualified W.P.S. Once qualified the welder must always work within the extent of approval of any properly qualified W.P.S. and his W.P.Q.
The welder who qualifies the P.Q.R. is automatically approved within the limits specified in QW304, QW305 and QW303. Ref QW301.2.

WELDER PERFORMANCE QUALIFICATION - PART 4

ROOT PASS  UPHILL 3G 

Starting the root weld did not require a preheat as the temperature was about 70 degrees outside. To start the root I got comfortable and started to weld. The technique I used was a side to side weave. I hold the sides of the bevel where the bevels edge feathers into the backing bar until I could see the arc of the electrode start to roll to that side. Once the arc is rolled and the flux is burned off on that side of the electrode, I weave onto the other side, and keep repeating that process. By allowing the arc to roll on the electrode it penetrates the bevel and gives the electrode a chance to ride up on the bevel for a moment. This helps to avoid slag inclusions. I used three welding electrodes and had two restarts. Here is the root weld cleaned with a wire wheel and as the procedure states it was inspected.

“The root of the weld shall be inspected, and there shall be no evidence of cracks, incomplete fusion, or inadequate joint penetration.

FINISHED AND CLEANED

FILL PASS

For the hot pass or fill pass I used the same technique as the root weld. That is holding the sides and rolling the arc until the weld rides up onto the side of the bevel. I used four electrodes and had three restarts.
Again I waited for the plate to cool and lightly grinded it down. I did not have to grind it, but why risk getting a slag inclusion. As you can see the first restart was a little rough.

Cover Pass and Cap.

The cap was done using a weave technique holding the corner of the bevel until it was filled and the moving onto the other side. If you do not wash weld properly into the corner of the bevel you run the chance of not penetrating the test coupon properly. On the cap of the weld I used four electrodes. Here is the picture of the cap weld.

“The face of the weld shall be flush with the surface of the base metal, and the weld shall merge smoothly with the base metal. Undercut shall not exceed 1/32 in. (1 mm). Weld reinforcement shall not exceed 1/8 in. (3 mm)” 

WELDER PERFORMANCE QUALIFICATION - PART 3

TEST COUPON PREPARATION as per wps

QUALIFICATION FOR GROOVE WELD POSITION 3G AS PER  ASME 1X

•  Welding Process. SMAW
•  Vertical Progression. Up
•  Joint Type. Butt
•  Backing. Yes
•  Backing Material. ASTM A36
•  Root Opening. 1/4 to 5/16
•  Grove Angel. 45 degrees
•  Back Gouge. No
•  Base Metal. ASTM A36
•  Type or Grade. Steel
•  Thickness. Groove. (in) .375
•  Filler Metals AWS Specification. A5.1
•  Filler Metals AWS Classification. E7018
•  Electrode Diameter. 1/8
•  Amps. 90 to 140
•  Electrode Characteristics Current. DCEP
•  Shielding Electrode Flux (class). 4
•  Stringer or Weave. Either
•  Multi-Pass or Single Pass (per side). Multiple
•  Interpass Cleaning. Mechanical or Wire Brush

PROCEDURE:

1. Grind all hot roll scale adjacent to the bevel, 1” on the front and ¼” back side of the test plate.
2. Grind off all oxidation on the bevel to bare metal. Re-check the bevel angle for the correct angle.
3. Grind all the hot scale off the backing bar to clean metal.
4. The inspector will check the preparation before fitting-up test pieces.
5. After the fit-up is completed the inspector will check all the fit-up specifications
6. Now the test will be placed in the fixed position. The test piece will be marked in position with a marker and the inspector may see the test anytime during the testing. (DURING THE TEST, THE PIECES SHALL NOT BE MOVED IN ANY DIRECTION AND OR REMOVED FROM THE TESTING PLACE WITHOUT THE INSPECTORS APPROVAL.)
7. The root pace shall be inspected.
8. Required temperatures. for example ASTM A36, 1/8” to ¾” thick base metal. Minimum preheat and interpass temperatures shall be as follows. When the base temperatures is below 32 degrees, the base metal shall be preheated to a minimum of 70 degrees and the minimum interpass temperature shall be maintained during welding.

                                                                                 

WELDER PERFORMANCE QUALIFICATION - PART 2

ACCORDING TO ASME

QW-100.2 In performance qualification, the basic criterion
established for welder qualification is to determine
the welder’s ability to deposit sound weld metal. The purpose
of the performance qualification test for the welding
operator is to determine the welding operator’s mechanical
ability to operate the welding equipment.

This Article is about passing the ASME 3G SMAW welding certification,. The purpose of this article is to help anyone out there who is about to take or conduct these tests & understand the welding procedure and help  them a visual understanding of this welding certification.

The ASME SECIX & AWS D1.1 SMAW 3G welding certification by itself certifies a welder to weld in the flat, horizontal, and vertical positions, without taking the flat and horizontal welding certifications.

 ASME sec IX , the chart  461.9 specifies test positions and corresponding qualification positions

 * PLATE WELDER CAN WELD PIPE BUT OD OVER 24''

Approval Range

Extent of approval is very well explained in QW461.9. Take particular note of welding positions which are also explained in QW461, for example to qualify a fillet weld in the normal horizontal-vertical position with a groove weld, the groove weld must be qualified in at least the 2G position. The welding positions defined in QW461.1.& QW461.2 should be referred to in the WPS. The position designations: 1G ,2G ,3G ,4G ,5G ,6G (Groove Welds) and 1F ,2F ,3F ,4F (Fillet Welds) are test positions 

WPS AND PQR CHECKLIST

AWS FILLER METAL SPECIFICATION

Welding Electrode Classification by American AWS-ASTM System -
E XX XX or E 60 1 2
E XXX XX or E 100 15
Letter E signifies that electrode is suitable for metal (electric) arc welding. XX/XXX
First two or three digits indicate minimum tensile strength of weld metal in thousands of pounds per sq. inch, e.g. 60,000 and 100,000 lbs/sq. inch. Other values of XX and XXX are 45, 70, 80, 90 and 120.
Last but one digit indicates the welding position. It can be represented by numbers like 1, 2 and 3 which indicate that welding can be carried out in any position, flat and horizontal positions, and flat position respectively.
   
Last digit which may be 0, 1, 2, 3, 5 or 6 tells about power (2): supply, type of covering, type of arc, penetration characteristics, etc.
(a) Electrode is meant for metal (electric) arc welding,
(b) It possesses a minimum tensile strength of 60,000 pounds per Square inch,
(c) It can weld satisfactorily in all positions,
(d) Electrode covering has a high titania (rutile) content, is bounded with sodium silicate, can be operated on DCSP or AC, produces medium penetration, heavy slag, a convex weld bead appearance and a medium quality weld deposition.

WPS AND PQR

 A Welding Procedure Specification (WPS)

It is a formal written document describing welding procedures, which provides direction to the welder or welding operators for making sound and quality production welds as per the code requirements . The purpose of the document is to guide welders to the accepted procedures so that repeatable and trusted welding techniques are used. A WPS is developed for each material alloy and for each welding type used. Specific codes and/or engineering societies are often the driving force behind the development of a company's WPS. A WPS is supported by a Procedure Qualification Record (PQR or WPQR). A PQR is a record of a test weld performed and tested (more rigorously) to ensure that the procedure will produce a good weld. Individual welders are certified with a qualification test documented in a Welder Qualification Test Record (WQTR) that shows they have the understanding and demonstrated ability to work within the specified WPS.

Within the WPS a number of essential variables are identified. These essential variables are those features of the procedure that, if changed outside a range of approval, will result in an unacceptable change in the mechanical properties or defect level of the weld, invalidating the WPS and making re-approval necessary.

It lists the pre-and post-weld operations including heat treatments,machining, grinding and dressing of the weld alsodetails of  the welding variables and the run sequence; and may specify the acceptance criteria and inspection methods.

 The purpose of the WPS is to ensure that acceptance criteria can be met consistently, including mechanical properties and defectlevels. It is also useful in enforcing quality control procedures, in standardisingon welding methods, production times and costs and in controlling production schedules. Its prime purpose, however, is to give the welder clear,unequivocal instructions on how a weld is to be made. 



 EN ISO 15609-1 (formally EN 288 Part 2)  European Standard For Welding Procedure Specifications
  

EN ISO 15609 Defines the contents of a Welding Procedure Specification in the form of a list of information that should be recorded.  For some applications it may be necessary to supplement or reduce the list. For example only in the case of a procedure requiring heat input control would there be a necessity to quote travel speed or run-out length for manual processes.

 ASME IX  American Boiler and Pressure Vessel Code 

QW 250 Lists the variables for each welding process, all the variables stated should be addressed.  The range permitted by the WPS is dictated by the PQR or PQR’s used to qualify it. 

     Common to all Processes        .

• Procedure number
• Process type
• Consumable Size, Type and full Codification.
• Consumable Baking Requirement if applicable
• Parent material grade and spec.
• Thickness range.
• Plate or Pipe, Diameter range
• Welding Position
• Joint Fit Up, Preparation, Cleaning, Dimensions etc.
• Backing Strip, Back Gouging information. 
• Pre-Heat (Min Temp and Method)
• Interpass If Required (Maximum Temperature recorded )
• Post Weld Heat Treatment. If Required (Time and Temp)
• Welding Technique (weaving,max run width etc.)
• Arc Energy Limits should be stated if impact tests are required or if the material being welded is sensitive to heat input.      

Standard Welding Procedures Specifications  (SWP's)

 
Standard welding procedures listed in annex E of ASME IX can be purchased from the 'American Welding Society' and used without qualifying a PQR.  Section V of ASME IX gives details of essential variables and restrictions.  A successful welder performance qualification must be carried out to demonstrate the SWP's before a manufacturer can use it. 

PQR ( PROCEDURE QUALIFICATION RECORD) 

PQR's are not required if Standard Welding Procedures are used.

This document contains details of the welding test, it must include details of all the parameters listed as variables in tables QW250 to QW265 for each process involved and all the destructive test results.

The relevant variables for each type of welding process are clearly defined in tables QW250 to QW265. The left hand column of each table defines the section and paragraph where each variable and its application to the table is explained in the code. 

Welding Variables :-

Variables used in a welding procedure test are divided into 3 categories :-

• Essential Variables Are variables that have a significant affect on the mechanical properties of a joint. They must not be changed except within the limits specified by this code. e.g. Material thickness range, Material Group etc.

• Non-Essential Variables Are variables that have no significant affect on mechanical properties. They can be changed without re qualification of the PQR.

• Supplementary Variables Are variables that have an affect on the impact properties of a joint. They are classed as Non-Essential if impact testing is not required. 

All variables listed as essential, non-essential or supplementary should be addressed on both the WPS and the PQR. If any of the variables do not apply to the particular application then they should be specified as not applicable.

Joint Configuration 

Either plate or pipe can be used for the test piece (plate approves pipe and vice versa ref. QW211), any welding position approves all positions providing no impact tests are required ref. tables QW250 to QW265 and any joint geometry approves all geometry's, e.g. single V, double V, U prep, backed or unbacked.

A butt or groove weld approves branch and fillet welds but not the converse, ref. QW202. Non pressure retaining fillet welds in pipe or plate can be tested but they must be double sided if plate and at least the dimensions illustrated in QW462.4a, ref. QW202.2c. Pressure retaining branch welds must be qualified by groove (butt) welds.

Material Grouping 

Materials are assigned P numbers in QW420; a test in one P number approves all materials listed under that P number, except where impact tests are required then approval is restricted to materials listed in the group number within the P number. Other P number groupings are permissible ref. QW424.1 for details. Ref QW 424.1 for further details.

It is normally permissible if the material is not listed in QW422 to assign it to a P number which lists materials with the same metallurgical and mechanical properties although this is not in strict conformance with the code. Typically BS1501 151 430A low carbon steel could be regarded as P1 and stainless steels such as 316, 304 as P8.

Note P5, 9 & 10 are divided into sub groups eg 5A,5B etc., Treat each sub group like a separate P Number

Dissimilar materials are acceptable providing they are compatible. For example P1 to P8, but this does not cover P1 to P1 or P8 to P8.

Note S numbers are for pipework to B31, a P number covers an S number but not the converse

Consumables 

The ASME code uses its own specifications for consumables SFA. which is almost identical to the AWS specification.

NOTE A change in consumable is only permissible providing it has the same F number and A number (if applicable) as the P.Q.R..
 

Thickness Limits 

Thickness limits Groove welds. See QW451 for precise details. 

• When Impact tests are required the minimum thickness approved is restricted.  See QW403.6
• More than one PQR may be required to qualify dissimilar thickness

The thickness little 't' of deposited weld metal for each process involved is approved from 0 to 2xt except:-

• MIG/MAG (GMAW/FCAW) dip transfer weld of deposited thickness less than ½" approves maximum thickness of 1.1 x t only Ref: QW255 (QW403.10)

• If any Pass in a single or multipass weld > ½" then the thickness approval equals  1.1xT

Dissimilar Thickness QW202.4:-

 The thicker and thinner part must be qualified, Except P8 and P4X the thinner part can be qualified if no Impacts and test coupon > 6mm thick.

Thickness limits for fillet welds as per QW462.4a or QW462.4d qualify all fillet weld sizes on all base material thicknesses and all diameters in one test.

Testing Requirements (Ref QW 463 for location of specimens)

Unlike EN288 there is no requirement for any non-destructive testing such as radiography or MPI/DPI, although I would recommend radiography for butt welds. 

The testing requirement for groove welds are as follows:-

• Two Transverse tensile tests (QW150).

• Two Root bends and Two face bends unless the plate thickness exceeds 3/8" then 4 side bends are required. All bend tests should be done to QW160 using the correct former ref. QW466 to an angle of 180 degrees. Longitudinal (all weld) bend tests are not recommended unless the base/weld materials differ markedly in bending properties.  See QW 466 for exceptions and precise details.

The testing requirement for fillet welds on plate is 5 macro sections only, for Pipe fillet welds 4 macro sections. No fracture test required.

information to give direction to the welder and should address all variables associated with the welding process defined in QW250 including non essential and supplementary.

A WPS can combine welding processes from other PQR's but all the relevant variables must be addressed including parent metal thickness. There is an exception to this rule for root runs from PQR's that are greater than 1.5 inches thick (38.1mm), see code for details.