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Square Groove Butt Joint Welds (1995 п. зн.)

Good quality single pass welds up to 5/16-in. thick can be made using the square groove butt joint without root opening and with suitable backing. W eld reinforcement, which tends to become excessive for thicker welds, can be controlled by adjusting the root opening. Variations in root opening, alignment of welding wire with the joint, and the amount of weld metal required generally limit the thickness of this type of weld to 3/4-in. Two pass welds up to 5/8-in. thick are made without root opening. It is essential in two-pass welds that the edges be closely butted since weld backing is not used. The maximum permissible root opening is 1/32-in. unless the joint is backed sufficiently to prevent the welding composition from flowing through the root opening. With such support greater root openings can be used. When the root opening exceeds 1/16-in., however, the opening should be closely filled with submerged arc welding flux ahead of the weld. The maximum root opening is approximately 1/8-in. because of the difficulty of refusing the welding flux at the base of the first pass weld. If the root gap is maintained constant for the entire length of the seam, plate up to 3/4-in. can be welded with square butt joints. The first weld is a backing weld made on the reverse side of the joint; the work is then turned over and the finishing weld is made. The finishing weld penetrates down into and refuses a portion of the backing weld to ensure a continuous weld structure throughout the plate thickness.

A satisfactory method of getting the required penetration of the finishing weld without excessive reinforcement is to back gouge a groove 1/8 to 5/16-in. deep in the top of the joint after the backing weld has been made. When gouging is used, no additional preparation or cleaning is needed except to remove any adhering slag. The advantage of the square groove butt joint is that it requires a minimum of edge preparation yet produces good quality welds with adequate penetration.

From (http://www.esabna.com/EUWeb/SA_handbook/585sa2_28.htm)

2.5 Terminological vocabulary to the text “Square Groove Butt Joint Welds”. Try to memorize the following words and word combinations.

1. square butt groove – подготовка(разделка) стыкового соединения без скоса кромок;

2. weld backing – подкладка под шов;

3. to penetrate [ 0penitreit]– проникать, проплавлять;

4. root face – поверхность притупления( кромки);

5. single pass - однопроходный;

6. excessive [ik0sesiv], adv – чрезмерный, избыточный;

7. alignment [Q0lainment], n – расположение по одной линии, выравнивание;

8. to adjust [Q0dGqst], v – настраивать, регулировать;

9. essential [i0sen(t)S(Q)l], adj – обязательный, непременный;

10. permissible [pQ0misQbl], adj - допустимый;

11. sufficiently [sQ0fiS(Q)ntli], adv - достаточно;

12. composition, n – структура, состав;

13. to maintain [mein0tein], v – поддерживать, сохранять;

14. to refuse [ri0fjuz], v – зд. переплавлять;

15. gouging [0gaudGiN]– поверхностная резка, строжка;

16. adhering [ Qd0hiQriN] slag – прилипший шлак.

Word Study

2.6 Read the words correctly. Consult the dictionary if necessary.

Sufficiently, adjusting, approximately, amount, permissible, maintain, reverse, gouge, throughout, adhere, adequate, ensure.

2.7 Translate the following word combinations into Russian.

good quality single pass welds up to 5/16-in. thick; a square groove butt joint without root opening; weld reinforcement; alignment of welding wire with the joint; the amount of weld metal required; two pass welds up to 5/8-in. thick; submerged arc welding flux ahead of the weld; the welding composition; a satisfactory method of getting the required penetration; the finishing weld without excessive reinforcement.

2.8 Translate the following sentences into Russian paying attention to the underlined words :

1. Welders must wear an approved helmet, gloves, and protective clothing.

2. The power source may also be a capacitor-discharge type. 3. Weld reinforcement, which tends to become excessive for thicker welds, can be controlled by adjusting the root opening. 3. Submerged arc welding can be used to make horizontal fillet welds.4. When the root opening exceeds 1/16-in., the opening should be closely filled with submerged arc welding flux ahead of the weld. 5. Arc stud welding may be done using a dc power source similar to those used with the shielded metal arc welding process. 6. Prior to welding, the studs generally have a small nib or bump which is to help initiate the arc. 7. Current and gas flow rates must be carefully regulated to prevent too large a keyhole. 8. The welder should wear flash goggles, approved clothing, safety shoes, and leather gloves. 9. Single pass welds up to 5/16-in. thick can be made using the square groove butt joint without root opening. 10. Friction welding is a specialized process and has applications only where a sufficient volume of similar parts is to be welded because of the initial expense for equipment and tooling.

2.9 Translate the following sentences into Russian paying attention to the underlined words:

1. Two pass welds up to 5/8-in. thick are made without root opening. 2. The joint is backed sufficiently to prevent the welding composition from flowing through the root opening. 3. If the root gap is maintained constant for the entire length of the seam, plate up to 3/4-in. can be welded with square butt joints. 4. The work is then turned over and the finishing weld is made. 5. A satisfactory method of getting the required penetration of the finishing weld without excessive reinforcement is to back gouge a groove 1/8 to 5/16-in. deep in the top of the joint after the backing weld has been made. 6. When gouging is used, no additional preparation or cleaning is needed except to remove any adhering slag. 7. A backing weld is made on the reverse side of the joint. 8. The heat-affected zone includes that portion of the base metal that has not been melted. 9. However, the structural or mechanical properties of the metal have been altered by the welding heat. 10. Metal thicknesses up to 76cm have been welded with this process.

2.10 Match the two halves of the sentence fragments to make logical statements.

2.11 Answer the following questions.

1. How can good quality single pass welds up to 5/16 inch thick be made? 2. What limits this dimension and how can we overcome this limitation? 3. What parameters limit the thickness of this type of weld to 3/4 inch? 4. Why is it essential that the edges in two-pass welds be closely butted? 5. How can we prevent the welding composition from flowing through the root opening? 6. What should be done if the root opening exceeds 1/16 inchт? 7. Why is the maximum root opening limited? 8. How does gouging simplify the process? 9. What is a satisfactory method of getting the required penetration of the finishing weld without excessive reinforcement? 10. What is the advantage of the square groove butt joint?

2.12 Make up a summary in English of the text “Square Groove Butt Joint Welds”.

2.13 Project Work. Choose several plate thicknesses within the proper range and speak about joining these plates using the information from the text and the Internet. You may simulate this process on your computer (make up a presentation) and demonstrate the results to your group-mates.

2.14 Read the text paying attention to the active terminological vocabulary.

Single-V Groove Butt Joint Welds (2542 п. зн.)

S ingle-V Groove with Root Face is used with non-fusible backing for single-pass butt welds of 5/16-in. or greater thickness. For most industrial applications, the maximum thickness is in the neighbourhood of 1-1/4 to 1-1/2-in. The root face has several advantages. The square edges simplify assembly.

Excellent penetration and reinforcement can be obtained and normal practical variations in voltage, current, welding speed, and edge preparation cause minimum damage to the backing. Relatively small quantities of wire are used because V preparation gives the desired penetration without excessive current and the volume of the V is considerably less than that required by other welding methods. With non-fusible backing, the root face dimension is 1/8 to 3/16-in. Root gap should not exceed 1/16-in. Fusible metallic backing is also used with this preparation with a root gap of at least 1/8-in. The single-V groove butt joint with root face and without external backing is also used for two pass welds where plate thickness exceeds 5/8-in. The first weld, usually the larger, is the backing weld made in the V side of the joint; the work is then turned over and the finishing weld made on the flat side. The finishing weld penetrates down into and refuses a portion of the backing weld to ensure complete penetration.

The root face is approximately 3/8-in. for all commercially welded plate thicknesses. The plate edges must be tightly butted (1/32-in. maximum gap) as with the square butt joint. When the welding composition is retained by a support below the joint, slightly greater root gaps are permissible; if the root gap exceeds 1/16- in., submerged arc welding flux should be tamped into the gap ahead of the weld.

T he Single-V Groove without Root Face is commonly used for nearly all thicknesses when using submerged arc backing flux. It is not commonly used below 3/8-in. thickness since adequate penetration can be obtained for these thicknesses without bevelling. The single-v groove butt joint without root face must always have weld backing since the mass of metal at the joint root is not sufficient to provide weld metal support. Reasonable misalignment in fit-up and variation in root gap can be tolerated when using submerged arc backing flux because the granular material will shift to accommodate them. Copper backing is not recommended because of the tendency of the weld metal to fuse to the backing piece. Fusible metallic backing is acceptable if there is no objection to its remaining as part of the completed weld.

From (http://www.esabna.com/EUWeb/SA_handbook/585sa2_28.htm)

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