Гричин С.В., Ульянова О.В. - Английский язык для инженеров сварочного производства, страница 6

Welding made possible a quantum jump in pressure attainablebecause the process eliminated the low structural efficiency of the rivetedjoint. Welding was widely utilized by industry as it strove to increaseoperating efficiencies by the use of higher pressures and temperatures, all ofwhich meant thick-walled vessels.

But before this occurred, a code forfabrication was born from the aftermath of catastrophe.On April 27, 1865, the steamboat Sultana blew up while transporting2200 passengers on the Mississippi River. The cause of the catastrophe wasthe sudden explosion of three of the steamboat's four boilers, and up to 1500people were killed as a result. Most of the passengers were Union soldiershomeward bound after surviving Confederate prison camps.

In anotherdisaster on March 10, 1905, a fire tube boiler in a shoe factory in Brockton,Mass., exploded, killing 58, injuring 117 and causing damages valued at$250,000. These two incidents, and the many others between them, provedthere was a need to bring safety to boiler operation. So, a voluntary code ofconstruction went into effect in 1915 - the ASME Boiler Code.As welding began to be used, a need for nondestructively examiningthose welds emerged. In the 1920s, inspectors tested welds by tapping themwith hammers, then listening to the sound through stethoscopes.

A dead33sound indicated a defective weld. By 1931, the revised Boiler Code acceptedwelded vessels judged safe by radiographic testing. By this time, magneticparticle testing was used to detect surface cracks that had been missedradiographic testing. By this time, magnetic particle testing was used todetect surface cracks that had been missed by radiographic inspection.

In hishistory of the ASME Code, A. M. Greene, Jr., referred to the late 1920s andearly 1930s as "the great years." It was during this period that fusion weldingreceived widespread acceptance. Nowadays, thousands of individuals whomake their living in welding live and breathe the ASME Code every minuteof the working day.In 1977, Leonard Zick, chairman of the main committee of the ASMECode, said, "It's more than a code; the related groups make up a safetysystem. Our main objective is to provide requirements for new constructionof pressure-related items that, when followed, will provide safety to thosewho use them and those who might be affected by their use.

"Reading 316You will read four texts about Welding's Vital Part in MajorAmerican Historical Events. Before you read suggest your answers to thefollowing questions.1. How can welding influence the history of a country?2. In what fields of industry, in your opinion, is welding especiallyimportant?3. What modern machines and structures cannot be produced withoutwelding processes?4. What welding process, arc or gas ones, has played a more important part indeveloping new technologies?17Look through the texts and find out what the following figures relate to.140 20 5171 2200500,000 586,000 17,0001945 525 531 271080 373 500 52 48,6120176,000Model: 2200 - 2200 passengers were killed on the Mississippi River whenthe steamboat Sultana blew up.3418Divide into four groups, each group reading one of the four texts. Fillin the table below for your text.Time periodBranchIndustryof Types of weldingAchievementsWelding's Vital Partin Major American Historical Events1ShipbuildingThe finest hours for U.S.shipbuilding were during WorldWar II when 2710 Liberty ships,531 Victory ships and 525 T-2tankers were built for the wareffort.

Through 1945, some 5171vessels of all types were constructedto American Bureau of Shipping (ABS) class during the MaritimeCommission wartime shipbuilding program. At this time in shipbuildinghistory, welding was replacing riveting as the main method of assembly.The importance of welding was emphasized early in the war whenPresident Roosevelt sent a letter to Prime Minister Winston Churchill, who issaid to have read it aloud to the members of Britain's House of Commons.The letter read in part, "Here there had been developed a welding techniquewhich enables us to construct standard merchant ships with a speedunequaled in the history of merchant shipping."The technique the President was referring to was undoubtedlysubmerged arc welding, which was capable of joining steel plate as much as20 times faster than any other welding process at that time.During this period of assimilation, eight Liberty ships were lost due toa problem called brittle fracture.

At first, many blamed welding, but historywould soon prove that the real cause of brittle fracture was steels that werenotch sensitive at operating temperatures. The steel was found to have highsulfur and phosphorus contents. On more than 1400 ships, crack arrestorswere used to prevent crack propagation. No crack was known to grow pastan arrestor. This safeguard helped reduce casualties from 140 to 20 permonth.352LNG TankersA triumph of the code was the hugealuminum spheres built by GeneralDynamics in Charleston, S.C. They werebuilt to criteria established by the U.S.Coast Guard and were based on SectionVIII, Division 1, of the ASME Code.At about 2 a.m. on October 2, 1976,the first welded aluminum sphere for aliquefied natural gas tanker was rolled outof a building in Charleston, then movedover to a special stand for finalhydropneumatic testing.It soon passed the test with flying colors.The sphere itself weighed 850tons and measured 120 ft (36 m) in diameter.

Each sphere consisted of morethan 100 precisely machined plates, "orange peel" in shape. The plates weregas metal arc welded together using 7036 lb (3166 kg) of filler metal. Totallength of the welds on each sphere was 48.6 miles. Completed spheres werebarged along the coast and delivered onto steel tankers under construction atGeneral Dynamics' shipyard in Quincy, Mass. This type of LNG tanker wasbased on the Moss-Rosenberg design from Norway.At General Dynamics' facility in Charleston, 80% of the metalworkingmanhours were spent welding. Much of the filler metal deposited inCharleston was 5183 aluminum.

The vertical joints were welded usingspecial equipment from Switzerland in which the operator rode in a customdesigned chair alongside the welding arc. At this distance, he was able tomonitor the weld and observe the oscillation of the 1Z.5 -mm diameter fillermetal. Actual welding was controlled remotely. About 30 weld passes wererequired for each joint.The massive equatorial ring waswelded outdoors. In this setup, nineheavily machined, curved aluminumextrusions had to be welded together.To do it, 88 GMA weld passes weremade from the outside and 60 morefrom the inside.3The Alaska PipelinePerhaps no single welding event in history ever received so muchattention as did the Alaska Pipeline. Crews of seasoned welders bravedAlaska's frigid terrain to weld this large-diameter pipeline, from start to36finish.

At one point, 17,000 people were working on the pipeline - 6% of thetotal population of Alaska. The entire pipeline only disturbed about 12 squaremiles of the 586,000 square miles of the state of Alaska.Welders were called upon to handle and weld a new steel pipe thickerand larger than most of them had ever encountered before, using electrodesalso new to most. And, the requirements were the stiffest they had ever seen.The U.S.

Department of the Interior and a new pipeline coordinatinggroup representing the state of Alaska instituted some changes. So, theoriginal specifications for field welding were tossed, replaced by muchstiffer requirements for weld toughness. Instead of the conventional pipelinewelding electrode planned originally for the bulk of field welding, the newrequirements required higher quality. The only electrode the engineers couldfind that met the new requirements was an E8010-G filler metal fromGermany, so it was soon flown over by the planeload. Some of the PipelineWelders Union out of Tulsa, Okla., then welding in Alaska, had used thiselectrode while working on lines in the North Sea, but most welders wereseeing it for the first time.One of the requirements was 100% X-ray inspection of all welds.

Thefilms were processed automatically in vans that traveled alongside thewelding crews.Welders worked inside protective aluminum enclosures intended toprotect the weld joint from the wind. Lighting inside the enclosures enabledwelders to see what they were doing during Alaska's dark winter.On the main pipeline, preheat and the heat between weld passes wasapplied at first by spider-ring burners. Induction heating was used laterduring construction.4High-Rise ConstructionAbout 30 years ago, steel construction went into orbit. The 100-storyJohn Hancock Center in Chicago and the 110-story twin towers of NewYork's World Trade Center were under construction. Above ground, theWorld Trade Center required some 176,000 tons of fabricated structuralsteel.

The Sears Tower came later. Bethlehem Steel Corp. had receivedorders for 200,000 tons of rolled steel products for the South Mall complexin Albany, N.Y. Allied Structural Steel Co. was reported to have usedmultiple-electrode gas metal arc welding in the fabrication of the FirstNational Bank of Chicago Building.In a progress report on the erection of the critical corner pieces for thefirst 22 floors of the 1107-ft (332-m) high John Hancock Center, an AlliedStructural Steel spokesman said various welding processes were being usedin that portion of the high-rise building. More than 12,000 tons of structural37steel were used in that section.

Webs and flanges for each interior H columnwere made up of A36 steel plate with thicknesses up to 6172 in. (16.5 cm).The long fillet welds at the web-to-flange contact faces were made using thesubmerged arc process, while the box consumed in shop fabrication for thisbuilding, while 165,000 lb (74,250 kg) of weld metal was consumed duringfield erection. Weld metal consumption in shop fabrication for the U.S. SteelBuilding in Pittsburgh, Pa., reached 609,000 lb (274,050 kg).During this same period, Kaiser Steel Corp. had used the consumableguide version of electroslag welding to deposit 24,000 welds in the Bank ofAmerica world headquarters building in San Francisco. At the time, thisbuilding was regarded as the tallest earthquake-proof structure ever erectedon the West Coast.

In terms of welding, one of the most intensive structuresbuilt during this period was NASA's Vertical Assembly Building on MerrittIsland, Fla. Shop-welded sections for this giant structure consumed 830,000lb (373,500 kg) of weld metal.For the World Trade Center, Leslie E. Robertson, a partner in charge ofthe New York office of Skilling, Helle, Christiansen, Robertson, said acomputer was used to produce the drawing lists, beam schedules, columndetails and all schedules for exterior wall panels.