Weld seam elevated temperature strength and notch sensitivity test sample thereof
Technical field
The present invention relates to a kind of weld seam elevated temperature strength and notch sensitivity test sample thereof, belong to materials science field.
Background technology
Along with China's development of electric power industry; Many high parameter high capacity fired power generating unit put into operation in succession; Power station high temperature and high pressure steam pipeline extensively adopts high-alloy steel; Like P91, P92 or the like, be the problem that domestic and international design, manufacturing, operation, maintenance, supervision and inspection personnel are extremely paid close attention to intensity, security, reliability and the serviceable life of these high-alloy steel jet chimney weld seams always.Along with the high temperature long-time running, the safety issue of weld metal becomes increasingly conspicuous.Show that mainly along with the high temperature long-play, the decline of its elevated temperature strength and weld metal are to the sensitive question of breach.Performance variation law under research and grasp weld metal act on when high temperature is long has important theory to the safe operation that guarantees the high-temperature metal parts and is worth and practical significance.
For obtaining to move the back performance variation law when weld metal high temperature is long, Erichsen test when needing the butt welded seam metal to carry out high temperature length.The present prior standard method of inspection, sample mainly contains circular specimen, template sample and homogeneous tube tensile sample, and the test section sectional area is invariable usually.As shown in Figure 1, Fig. 1 is conventional tabular lasting tensile sample object construction synoptic diagram.
Should comprise weld seam, heat-affected zone and mother metal for the weld seam test section; Because weld metal intensity is far above mother metal and heat-affected zone; Especially P91 steel weld seam; Conventional tensile sample generally all breaks at weld heat-affected zone, and the strength of welded joint that records is actually weld heat-affected zone intensity, and the weld metal actual performance is difficult to record.Power station its safe operation of high temperature and high pressure steam pipe welding seam performance impact for research weld metal performance, needs the butt welded seam metal to carry out Performance Detection usually; Conventional stretching; Comprise test methods such as normal temperature stretching, drawing by high temperature and creep rupture strength, the test section cross-sectional area is generally invariable, because weld strength is far above mother metal and heat-affected zone; Sample is big multibreak in the heat-affected zone, and the lateral performance of weld metal has no way of learning.
Summary of the invention
In order to solve technical matters of the prior art; The invention provides a kind of weld seam elevated temperature strength and notch sensitivity test sample thereof; Its objective is in order to provide a kind of method of testing to guarantee that tensile sample breaks at welded seam area, thereby record the notch sensitivity of weld metal intensity and weld metal.
The present invention realizes through following technical scheme:
Weld seam elevated temperature strength and notch sensitivity test sample thereof comprise that two ends are thick, middle thin elongate in shape sample, and two ends are bare terminal end, the centre is a test section.The bare terminal end at said sample two ends is provided with inwardly recessed rounding off section to middle test section direction, and test section is provided with breach.
Described breach is opened the side at test section.
Described breach is opened on weld metal.
Described breach is located at the centre position of test section.
Described is rectangular configuration by test agent, and the test width of bare terminal end is 24mm, and monolateral length is 20mm, and center test section length is 35-45mm, and thickness is 3mm, the dark 2mm of test section central indentation, and wide 2mm, length equals by the sample thickness of having a try.
Advantage and effect:
The present invention is a kind of weld seam elevated temperature strength and notch sensitivity test sample thereof; Owing on sample, added a kind of variable cross section band notched specimen; Breach is opened in the weld metal part, and it can guarantee that sample breaks in weld metal, and can record weld metal intensity and to the susceptibility of breach.Because there are defectives such as lack of penetration unavoidably in the root of weld, weld metal intensity and foundation is provided to the security that the measurement of the susceptibility of breach can be the long-time running under HTHP of assessment weld seam.Solved traditional sample and can't measure problems such as weld strength and weld seam notch sensitivity, this sample processing is simple, and process of the test is the same basically with conventional stretching test method.The blank of this technical field has been filled up in this invention, has bigger social benefit and economic benefit.
Description of drawings
Below in conjunction with accompanying drawing and embodiment the present invention is done further detailed explanation.
Fig. 1 is conventional tabular lasting tensile sample object construction synoptic diagram;
The lasting tensile sample object construction of the band breach synoptic diagram that Fig. 2 the present invention is done;
The test unit schematic diagram that Fig. 3 the present invention adopts;
Tensile test piece indentation, there proof stress was a 350MPa object construction synoptic diagram when high temperature that Fig. 4 the present invention is done was long;
Tensile test piece indentation, there proof stress was a 290MPa object construction synoptic diagram when high temperature that Fig. 5 the present invention is done was long;
Tensile test piece indentation, there proof stress was a 250MPa object construction synoptic diagram when high temperature that Fig. 6 the present invention is done was long.
Among the figure: test section 1, bare terminal end 2, breach 3, levelling device 4, leverage 5, charger 6, temperature survey and temperature control 7, sample chuck 8, sample 9, high-temperature heater 10.
Embodiment
Embodiment 1:
The present invention is weld seam elevated temperature strength and notch sensitivity test sample thereof, and is as shown in Figure 2, and sample 9 according to the invention is that strip is identical with conventional lasting sample, and two ends are thick, middle thin structure; Two ends are bare terminal end 2, and the centre is a test section 1, and the bare terminal end 2 at two ends is inside recessed rounding off section to middle test section 1 direction, and the middle part of test section 1 wherein is provided with breach 3.
Band notched specimen Weld Performance test sample of the present invention, stretching test method was identical when its test operation step was long with conventional high temperature, and difference is sample production; As shown in Figure 2, sample of the present invention is rectangular template, and two ends are that gripping section is identical with conventional lasting sample; The centre is a test section; Be provided with the rounding off section between two sections, test section wherein is notched rectangular shape, and breach is opened on weld metal.
Sample of the present invention is the rectangle sheet, and bare terminal end test width is 24mm, and monolateral length is 20mm, and center test section length is 35-45mm, and thickness is 3mm, the dark 2mm of central indentation, and wide 2mm, notch length equals sample thickness.
As shown in Figure 3, utilize sample of the present invention do experiment on conventional high temperature tension test machine, to accomplish, through the rupture time under the different stress of same temperature such as weld seam band notched specimen, mother metal band notched specimen, measure Weld Performance and weld seam notch sensitivity.During test; Sample 9 is clipped on the sample chuck 8 in the high-temperature heater 10; The heating furnace two ends seal with insulation material, and adjustment levelling device 4 makes sample transfer to the middle part of heating furnace 10, and energized heats up; Through temperature survey and temperature control 7 test temperature is risen to 540 ℃ of test temperatures, and keep constant temperature.After temperature reaches test temperature, load through leverage 5 and charger 6, adjust levelling device 4 again after loading is accomplished and make sample remain on the middle part of heating furnace 10.Under 540 ℃, do tension test when long, break, calculate rupture time, draw the corresponding relation of stress and rupture time until sample.
Embodiment 2:
Adopt square-section P91 button, test section sample sectional dimension is 7 * 3mm, and breach is opened in welded joints, the dark 2mm of opening, the wide 2mm of opening.Test temperature is 540 ℃, and 4 sample break place proof stresses are respectively 364MPa, 350MPa, 290MPa, 250MPa, and the sample fracture time is respectively 0,20,1582,9600 hour, and is extremely shown in Figure 6 like Fig. 4.
Adopt square-section P91 base metal test specimen, test section sample sectional dimension is 7 * 3mm, and breach is opened at test section middle part, the dark 2mm of opening, the wide 2mm of opening.Test temperature is 540 ℃, and 2 sample break place proof stresses are respectively 350MPa, 250MPa, and the sample fracture time is respectively 10,4220 hours.
Relatively more visible; Proof stress is that P91 button its rupture time under 540 ℃ of 350MPa and 250MPa is more than 2 times of P91 base metal test specimen; It is thus clear that under 540 ℃, the indentation, there weld strength is higher than mother metal, at high temperature (540 ℃) weld seam notch sensitivity is lower than mother metal.Stretch test result when test findings sees table 1:P91 weld seam and mother metal v-notch sample high temperature (540 ℃) length for details.