Упражнения

Упр.1. Найдите в тексте английские эквиваленты следующих слов и словосочетаний:

1. Соответствовать чему-либо; 2. в каждом отдельном случае; 3. односторонняя сварка на огнеупорной подкладке; 4. порошковая проволока; 5. электроды с контролируемым содержанием водорода; 6. обычная прочность; 7. жесткость выемки; 8. подходящий, надлежащий; 9. по усмотрению компании; 10. грамотный инспектор-контролер; 11. неразрушающие методы контроля; 12. признанный орган; 13. своевременно проверенный; 14. точные показания; 15. указания производителя.

Упр. 2. Переведите следующие слова и словосочетания из текста:

1.explicit indication; 2. to this effect; 3. unless otherwise specified; 4. ambient temperature; 5. covered electrodes; 6. flux-coated electrodes; 7. certified welder; 8. to man a welding machine; 9. in compliance with; 10. measuring instruments; 11. regular feed; 12. grade; 13. the rules of good practice; 14. recognized standards; 15. to facilitate positioning and assembly.

Unit 38. TYPES OF CONNECTIONS AND PREPARATION

The type of connection and the edge preparation are to be appropriate to the welding procedure adopted, the structural elements to be connected and the stresses to which they are subjected.

In general, butt connections of plating are to be full penetration, welded on both sides except where special procedures or specific techniques are adopted. Connections different from the above may be accepted by the Society on a case-by-case basis; in such cases, the relevant detail and workmanship specifications are to be approved. In case of welding plates with a difference in gross thickness equal to or greater than 3.00 or 4.00 mm , if the thinner plate has a gross thickness equal to or less than 10 mm, a taper having a length of not less than 4 times the difference in gross thickness is to be adopted for connections of plating perpendicular to the direction of main stresses. For connections of plating parallel to the direction of main stresses, the taper length may be reduced to 3 times the difference in gross thickness. When the difference in thickness is less than the above values, it may be accommodated in the weld transition between plates. The acceptable root gap is to be in accordance with the adopted welding procedure and relevant bevel preparation.

Butt welding on permanent backing, i.e. butt welding assembly of two plates backed by the flange or the face plate of a stiffener, may be accepted where back welding is not feasible or in specific cases deemed acceptable by the Society. The type of bevel and the gap between the members to be assembled are to be such as to ensure a proper penetration of the weld on its backing and an adequate connection to the stiffener as required.

When lengths of longitudinals of the shell plating within 0,6 L amidships, or elements in general, subject to high stresses, are to be connected together by butt joints, these are to be full penetration. Other solutions may be adopted if deemed acceptable by the Society on a case-by-case basis.

The work is to be done in accordance with an approved procedure; in particular, this requirement applies to work done on board or in conditions of difficult access to the welded connection.

In general, ordinary fillet welding (without bevel) may be adopted for T connections of the various simple and composite structural elements, where they are subjected to low stresses (in general not exceeding 30 N/mm2) and adequate

precautions are taken to prevent the possibility of local laminations of the element against which the T web is welded. Where this is not the case, partial or full T penetration welding is to be adopted. This applies particularly to members over than 12 mm thick constituting the whole or part of the engine seatings.

Fillet welding may be of the following types: • continuous fillet welding, where the weld is constituted by a continuous fillet on each side of the abutting plate; • intermittent fillet welding, which may be subdivided into chain welding, scallop welding, staggered welding.

Continuous fillet welding is to be adopted for watertight connections, for connections of brackets, lugs and scallops, at the ends of connections for a length of at least 75mm, where intermittent welding is not allowed. Continuous fillet welding may also be adopted in lieu of intermittent welding wherever deemed suitable, and it is recommended where the spacing is low.

In case of automatic or semi-automatic deep penetration weld, the throat thickness may be reduced. It may be required by the Society to be increased, depending on the results of structural analyses. The leg length of fillet weld T connections is to be not less than 1.4 times the required throat thickness.

The throat thickness of the welds between the cut-outs in primary supporting member webs for the passage of ordinary stiffeners is to be not less than the value obtained, in mm, from the special formula. The throat thickness of fillet welds connecting ordinary stiffeners and collar plates, if any, to the web of primary supporting members is to be not less than 0,35 tW, where tW is the web gross thickness, in mm.

When fillet welding is carried out with automatic welding procedures, the throat thickness may be reduced up to 15%, depending on the properties of the electrodes and consumables. However, this reduction may not be greater than 1,5 mm. The same reduction applies also for semi-automatic procedures where the welding is carried out in the downhand position.

VOCABULARY

Plating – листовая обшивка

Workmanship – качество работы

To approve – утверждать, разрешать

Gross thickness – общая толщина

Taper - конус

Weld transition –145 переходный участок (шва)

Root gap – зазор между свариваемыми кромками

Backing - подкладка

Flange – фланец, выступ

Stiffener – ребро \ элемент жесткости

Feasible - исполнимый

Longitudinal – продольный брус

T-connection - тавровое \Т-образное соединение

Lamination слоистость, расслаивание

engine seating – место установки двигателя

abutting plate – торцевая, стыкуемая плита

scallop weld – зубчатый, волнистый шов

staggered weld – шахматный шов

chain welding – цепная сварка -

bracket – скоба, консоль

lug – зажим, кронштейн

scallop – зубчатый край

throat thickness – толщина шва

web – перегородка, балка

leg of (fillet) – катет (углового шва)

downhand\downward position – нижнее положение шва