CN101699259B - Method for simulating bent pipe deformation by bending - Google Patents

Abstract

The invention provides a method for simulating bent pipe deformation by bending. The method is characterized by including the steps that: strip sample for bending the length of which is not less than 150mm is processed, the surface of the sample is required to be smooth without defect; even drawing is carried out on the side of the strip sample for bending along thickness direction, a horizontal line is drawn on the maximum surface in tension of the sample, points of intersection are formed between the horizontal line and evenly spaced vertical lines, separation distances of all points and sample size are measured accurately; bend cores with different diameters are selected according to test requirement, and bending test is carried out on a bending test device; separation distances of all points after bending are accurately measured, deformation is calculated by distance change of drawing before and after bending, and deformation=(separation distances of all points after bending-original separation distance)/original separation distance*100%. The invention can obtain samples with different stretch and compression deformations in one process by adopting bending test, time and material are saved, the simulation is more close to stress state of actual bend.

Description

A kind of method with crooked simulation bent pipe deformation

Technical field

The present invention relates to a kind of method, belong to station boiler steel pipe pipe bending technique field with crooked simulation bent pipe deformation.

Background technology

Need to experience distortion manufacture processes such as bend pipe in the station boiler manufacture process, the material require that deflection is bigger is done the thermal treatment of removing stress.In heat treatment process, the crystal grain of austenitic steel can be grown up, and influences performance.Therefore need heat-treat test to the steel pipe of different distortion amount, the grow up tendency and the prevention method of research crystal grain.For the sample of different distortion amount, need take different Technologies for Heating Processing.In order to obtain different deflection samples, domestic have the method for utilizing the acquisition different distortion amount sample that stretches, but tension test can only obtain the sample of stretcher strain, can not obtain the sample of compression deformation, and necking down appears in drawing process easily, and the specimen preparation success ratio is low.And adopt bending test once can obtain the sample of different stretch and compress variation, save time and material.

At present, boiler industry begins to use in a large number the fine grained austenite steel pipe, and thermal treatment is very big to the grain size influence, so need study the Technology for Heating Processing of different distortion dimension pipe, therefore, press for simply, easily going and effective method of proposition simulation different distortion amount.

Summary of the invention

The purpose of this invention is to provide a kind of method of simulating the different distortion amount.

In order to achieve the above object, technical approach of the present invention has provided a kind of method with crooked simulation bent pipe deformation, it is characterized in that step is:

Step 1, processing length are not less than the bending bar-shaped sample of 150mm, and the surface of this sample needs smooth and zero defect;

Step 2, evenly rule along thickness direction with the side of bar-shaped sample in bending, each standardized horizontal line on the maximum tension surface of sample or maximum pressure surface, article two, horizontal line forms intersection point with at interval uniform vertical line, accurately measures distance and specimen size between the each point;

Step 3, select the curved core of different-diameter according to the test needs, in the enterprising line bend test of bending test equipment;

Step 4, the accurate distance of measuring between the each point of crooked back are calculated deflection by the variable in distance between the line of crooked front and back, deflection=(each dot spacing-primary leading of crooked back)/primary leading * 100%.

Further, even line described in the step 2 is meant in bending circumferentially evenly rules along the every interval 10mm of thickness direction with the side of bar-shaped sample, is divided into 10 zones.

The present invention adopts bending test once can obtain the sample of different stretch and compress variation, saves time and material, and is more approaching with the stress state of actual elbow.

Description of drawings

Fig. 1 is the original state synoptic diagram of employed bending test equipment among the present invention;

Fig. 2 is the intermediateness synoptic diagram of employed bending test equipment among the present invention;

Fig. 3 is the end-state synoptic diagram of employed bending test equipment among the present invention.

Embodiment

Specify the present invention below in conjunction with embodiment.

Embodiment

A kind of method provided by the invention with crooked simulation bent pipe deformation, step is:

Step 1, processing length are not less than the bending bar-shaped sample of 150mm, and the surface of this sample needs smooth and zero defect.

Step 2, in bending with the side of bar-shaped sample along circumferentially evenly line of the every interval 10mm of thickness direction, at standardized the horizontal line in the maximum tension surface of sample, article two, horizontal line forms intersection point with at interval uniform vertical line, accurately measures distance and specimen size between the each point.

Step 3, select the curved core of different-diameter according to the test needs, in the enterprising line bend test of bending test equipment.The employed bending test equipment of present embodiment comprises crooked pressure head 1 as shown in Figure 1 to Figure 3.Crooked pressure head 1 satisfies following condition: the first, the diameter of crooked pressure head 1 should be stipulated in products standards.The second, crooked pressure head width should be greater than specimen width or diameter.Three, the depression bar thickness of crooked pressure head should be slightly less than crooked pressure head diameter.Four, crooked pressure head should have enough hardness.Be provided with two turnover panels 3 below crooked pressure head 1, the sample carrying plane that should be two turnover panels apart from l of 3 of turnover panels is the distance between two carrying planes during simultaneously perpendicular to horizontal axis.Determine according to following formula: l=(d+2a)+e, d is the width of crooked pressure head 1 in the formula, a is the thickness of sample, but e value 2～6mm.Turnover panel 3 is fixed on the gudgeon 4, can rotate around gudgeon 4 axis during test.Gudgeon 4 connects angle of bend indicator 5, indicates 0 °～180 ° angle of bend.Turnover panel 3 has wedge block 2, and the width of slide block 2 should be greater than the width or the diameter of sample, and should have enough hardness.Concrete use is: sample lies on the sample carrying plane of Apparatus for Bending at low-temp, the sample axis should with crooked pressure head 1 axis normal, the midpoint of crooked pressure head 1 between two bearings, sample is applied power continuously with certain speed make its bending, make sample be bent to 180 ° of angles at last, two arms are at a distance of predetermined distance and till being parallel to each other.

Step 4, the accurate distance of measuring between the each point of crooked back are calculated deflection by the variable in distance between the line of crooked front and back, deflection=(each dot spacing-primary leading of crooked back)/primary leading * 100%.

If adopting said method line up diameter is 45mm, wall thickness is that the steel pipe sampling of 9.2mm is tested, and its concrete steps and parameter are:

Step 1, intercepting band sample, through digging, grinding processing, specimen size is 150 * 12.5 * 9.2mm.

Step 2, bending are evenly rule along thickness direction with the side of band sample, since an end, are starting point apart from end points 25mm place, every standardized line of 10mm, draw 10 sections.Each standardized horizontal line on the maximum tension surface of sample and maximum pressure surface, two horizontal lines and intersection points of vertical lines formation are uniformly at interval accurately measured the distance between the each point, data following (mm): 9.76,10.10,9.72,10.08,9.90,9.86,9.82,10.02,9.78,9.86.

Step 3, selection diameter are the curved core of 25mm, in the enterprising line bend test of bending test equipment.

Step 4, the accurate distance of measuring between the each point of curved back, maximum tension surface data following (mm): 9.76,10.40,10.94,11.82,12.60,12.58,12.46,11.32,10.22,9.86.According to the length variations before and after crooked, calculate each section deflection and be respectively: 0,2.97%, 12.55%, 17.26%, 27.27%, 27.58%, 26.88%, 12.97%, 4.50%, 0.

Can obtain the sample of different stretch deflection by above step, obtain the sample of different compress variations as need, only need standardized horizontal line on the maximum pressure surface of original sample, this horizontal line and at interval uniform vertical line form intersection point, accurately measure the distance between the each point, repeat the sample that as above step can access different compress variations.

Claims (1)

1. method with bending simulation bent pipe deformation is characterized in that step is:

Step 1, processing length are the bending bar-shaped sample of 150mm, and the surface of this sample needs smooth and zero defect;

Step 2, evenly rule along thickness direction with the side of band sample in bending, since an end, apart from end points 25mm place is starting point, every standardized line of 10mm, draw 10 sections, each standardized horizontal line on the maximum tension surface of sample or maximum pressure surface, two horizontal lines with at interval uniformly vertical lines form intersection points, accurately measure distance and specimen size between the each point;

Step 3, select the curved core of different-diameter according to the test needs, in the enterprising line bend test of bending test equipment;

Step 4, the accurate distance of measuring between the each point of bending back, by the variable in distance calculating deflection between the line of crooked front and back, deflection=(preceding each dot spacing of crooked each dot spacing-bending of back)/crooked preceding each dot spacing * 100%.

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