Sobre la actuación de los comités de autodefensa Sobre la actuación de los comités de autodefensa

1. Name four steps (paragraphs) when looking for exemptions from impact testing.

2. When are impact tests always mandatory for welded joints?

3. When are impact tests always mandatory for non-welded joints?

4. What is the minimum design temperature allowed for a 1 ½” thick plate of SA-515 Gr. 70"

5. If the coincident Ratio is 0.6 for the plate of question number 4 what is its new minimum temperature with out impact tests?

UG-77 Material Identification

Overview

The material for pressure parts must be handled in a particular way per the Code. For instance, the Code specifies that materials for parts of a vessel should be laid out and marked in such a way as to easily maintain traceability after the vessel is completed.

Several techniques for identification markings are allowed and are described in this paragraph. Stamping is the preferred method of marking vessel parts; however, as built drawings and tabulation sheets are also acceptable. The manufacturer must maintain traceability to the original markings. For instance, when cutting parts for the vessel from plate the heat number stamped on the piece of plate should be transferred prior to cutting the plate. They may be transferred immediately after cutting if a provision for control of such transfers has been made in the Manufacturer's Quality Control System. If a particular material should not be die stamped, plates must be made and attached with the required markings. A record of these markings must be maintained which will allow positive identification of the vessel parts after construction.

If a Code vessel manufacturer buys parts that are formed, such as heads, from another manufacturer of the head shall transfer the markings as applies to the material specification that the part is made from. Only materials allowed by the Code can be used by the part manufacturer. In addition. the part Manufacturer must supply a Partial Data Report. A Manufacturer's Partial Data Report is not required if the part was formed or forged, etc., without the use of welding. The markings of the Part Manufacturer must be present on the part.

UG-93 Inspection of Materials Overview

The highlights of this paragraph are as follows:

1. Plate is the only pressure vessel material that must always have a Mill Test Report (MTR)or Certificate of Compliance (C of C) provided. The inspector shall examine these documents for compliance to the material specification.

2. All other product forms must be marked in accordance with their material specification. For examp1e, pipe marked SA- 106 gr. B.

3. All materials to be used in a vessel must be inspected before fabrication to find as best as is possible defects which would affect the safety of the vessel. The following describes the inspections required.

a. Cut edges of and parts made from rolled plate for serious laminations, shearing cracks, etc.

b. Materials which will be impact tested must be examined for surface cracks.

c. When forming a Category C corner joint as shown in figure UW-13.2 with flat plate thicker than ½”, the flat plate must be examined before welding by magnetic particle or dye penetrant nondestructive examination. Exceptions from this NDE are given for certain joints of figure UW-13.2 .

d. The inspector must assure himself that thickness and other dimensions of the material comply with the requirements of this Division.

e. The inspector must verify welded repairs to defects.

f. The inspector must verify that all required tests have been performed and are acceptable (Impact tests, NDE, etc.).

UG-116 Required Marking Overview

The marking applied to a vessel's nameplate or directly to its shell are described in this paragraph. It is important information. Often a vessel's Data Report is lost and the only information that is available is that found on the Name Plate or the shell itself In some cases the Name Plate is missing or sand blasted and not readable. The following is a listing of what is required by the Code to be present on the Name Plate.

1. The official Code U or UM symbol. If Inspected by the Owner/User of the vessel the word USER shall be marked on the vessel.

2. Name of the manufacturer preceded by the words "Certified by”.

3. Maximum allowable working pressure __________ psi at _______ °F. 4. Minimum design metal temperature _______ °F at ___________ psi. 5. Manufacturer's serial number.

6. Year built.

7. The type of construction used for the vessel must be marked directly under the Code symbol by the use of the appropriate letter as listed in the Code.

Type of Construction Letter(s)

Arc or gas welded W

Pressure welded (except resistance) P

Brazed B

Resistance welded RES

8. If a vessel is built using more than one type of construction all shall be indicated.

9. If a vessel is in a special service the lettering as shown below must be applied.

Lethal Service L

Unfired Steam Boiler UB

Direct Firing DF

11. When a complete vessel or parts of a vessel of welded construction have been radiographed in accordance with UW-11, the marking must be as follows:

“RT 1” When all pressure retaining butt welds, other than B and C associated with nozzles and communicating chambers that neither exceed NPS 10 nor 1 1/8” thickness have been radiographically examined for their full length in a manner prescribed in UW-51, full radiography of the above exempted Category B and C butt welds if performed, may be recorded on the Manufacturer' Data Report.

“RT 2" Complete vessel satisfies UW-11 (a)(5) and UW-11 (a)(5)(b) applied.

“RT 3” Complete vessel satisfies spot radiography of UW-11 (b).

“RT 4” When only part of the vessel satisfies any of the above.

*A separate section follows which is devoted to the meanings of RT markings:

12. The letters HT must be used when the entire vessel has been postweld heat treated.

13. The letter PHT when only part of the vessel has been postweld heat treated.

14. Code symbol must be applied after hydro or pneumatic test.

15. Parts of vessels for which Partial Data Report are required shall be marked by the parts manufacturer with the following:

"PART"

Name of the Manufacturer

The manufacturer's serial number.

These requirements do not apply to items like manhole covers, etc.

16. All required markings must be located in a conspicuous place on the vessel, preferably near a manhole or handhole.

UG-119 Nameplates Overview

In this paragraph are the details of nameplates, including such things as the size and methods of markings allowed. The nameplate must be located within 30” of the vessel and must be thick enough to resist distortion when stamping is applied. The types of acceptable

attachment types include welding, brazing, and tamper resistant mechanical fasteners of metal construction. Adhesive attachments may be used if the provisions of Appendix 18 are met. An additional nameplate may be used if it is marked with the words " DUPLICATE ". On previous tests some essay or multiple choice questions have come from this paragraph. As with all paragraphs UG-119 should be read entirely.

CODE SYMBOL Certified by

Johns Trailer and Vessel Welding

U

350 psi at 300°F W MAWP RT 1 -20°F at 200 psi HT L MDMT 0000001 S / N 1994 Year

UG-120 Data Reports Overview

Data Reports must prepared on form U-1 or U-1A for all vessels that the Code Symbol will be applied to. They must be signed by the Manufacturer and the Inspector. A single Data Report may represent all vessel made in the same day production run if they meet all of the requirements listed in UG-120.

A copy of the Manufacturer's Data Report must be furnished to the User and upon request the Inspector. The Manufacturer must either keep a copy of the Data Report on file for 5 years or register the vessel and file the Data Report with the National Board of Boiler and Pressure Vessel Inspectors.

A Manufacturer's Certificate of Compliance must be completed on form U-3 for all UM (unfired miniature) stamped vessels.

A Partial Data Report form U-2 or U-2A must be completed for parts of a vessel that require one (parts bought from other manufacturers such as formed heads made with welding). These forms must be attached to forms U-1 or U-1A as applies for the vessel to be marked with the Code Symbol..

A Partial Data Report form U-2 or U-2A must be completed for parts of a vessel that are ordered to repair a User's vessel.

If a vessel has any special service requirements (Lethal, Unfired Steam Boiler, etc.) compliance must be indicated on the appropriate "U" Form.

Since this article covers the requirements in general terms it is often given just cursory attention or skipped altogether. This is a mistake for anyone wishing to be competent in applying this section of the ASME Code.

It is mandatory to read every article of Section IX in order to apply the code rules and since many questions on an exam could come from this article alone, it should not be overlooked. As an example, the purpose of a welding procedure is given in paragraph QW-100.1. In the very given next paragraph, welders' performance qualification tests are addressed. In QW- 100.3 it is stated that a Welding Procedure Specification written and qualified in accordance with the rules of Section IX may be used in any construction built to the requirements of the ASME Boiler and Pressure Vessel Code or the ASME B-31 Code for Pressure Piping. In the next paragraph you are cautioned that other Sections of the Code state the conditions under which Section IX requirements are mandatory, in whole or in part.

Also in QW-120, QW-130 and QW-132 of this article, test positions are listed with written definitions and references to Article IV where illustrations of these positions are to be found.

Types and purposes of tests are addressed in the paragraphs of QW-141.1 through QW-141.5, and all the subsequent paragraphs contain explanations of the tests and examinations required. Acceptance criteria is listed for each type of test described.

Beginning with QW-190, other types of tests and examinations are listed, most notable being radiographic and liquid penetrant examinations. Here you are referred to Section V, and then told the acceptance standards of QW-191.2 and QW-195.2 respectively shall be met.

Article II. Welding Procedure Qualifications

In document Conclusiones y Recomendaciones Informe Final de la Comisión de la Verdad y Reconciliación (página 39-43)