37 results about "Bauschinger effect" patented technology

The present invention provides steel plate or steel pipe with small occurrence of the Bauschinger effect and methods of production of the same, particularly steel pipe used for steel pipe for oil wells or line pipe with a small drop in the compression strength in the circumferential direction due to the Bauschinger effect when expanded and methods of production of the same, that is steel plate or steel pipe with small occurrence of the Bauschinger effect characterized by having a dual-phase structure substantially comprising a ferrite structure and fine martensite which is dispersed in the ferrite structure. Further, this steel plate or steel pipe contains, by mass %, C: 0.03 to 0.30%, Si: 0.01 to 0.8%, Mn: 0.3 to 2.5%, P: 0.03% or less, S: 0.01% or less, Al: 0.001 to 0.01%, and N: 0.01% or less and a balance of iron and unavoidable impurities.

The invention discloses a method for determining thin plate reverse loading Bauschinger effect, and belongs to the field of thin plate stamping technology. The method comprises the following steps: 1) prestretching a to-be measured thin plate, unloading the prestretching force, then bending the thin plate, measuring deformation angle Z* after the thin plate rebounds; 2) measuring a series of the deformation angles Z* after the thin plate rebounds; 3) constructing a parameter model of the material of the to-be measured thin plate, endowing an initial value, and analog computing the thin plate rebounding angle to obtain a series of the deformation angles Z after the thin plate rebounds, comparing with the test result in step 2) till the difference of the two deformation angles reaches a preset threshold, and outputting a material parameter A which is obtained by calculating at the same time; and 4) carrying out finite element simulation by using the material parameter A to obtain a Bauschinger effect curve of the thin plate. The test apparatus and the data processing method are simple, mechanical testing data in larger strain can be obtained, influence factors are less and parameters are accurate.

The invention discloses X 60 pipeline steel with the thickness of 16-25 mm and a production method of the pipeline steel. The pipeline steel comprises chemical components as follows: 0.06 wt%-0.09 wt% of C, 0.25 wt%-0.35 wt% of Si, 1.55 wt%-1.69 wt% of Mn, 0.20 wt%-0.29 wt% of (Nb+Ti+V+Mo+Ni), no more than 0.010 wt% of P and no more than 0.003 wt% of S. The production method mainly comprises LF+VD, continuous casting and controlled rolling and controlled cooling. Obtained X 60 microstructure contains 42 %-46 % of lath-shaped ferrites, 32 %-38 % of acicular ferrites, 13 %-15 % of bainite, a small amount of M-A islands and fine dispersion precipitated phases; the phase interface bonding performance is good, the yield ratio is 0.66-0.76, and the grain size reaches 11.5-12.5 grades; and the welding performance is good, and the Bauschinger effect is low.

The invention relates to an apparatus and method for precisely detecting Bauschinger effect of repeated bending of a metal plate, the apparatus comprises a mechanics loading module and a plate clamping adjustable module fixed at the bottom of the mechanics loading module; the mechanics loading module is fixed and suspended through a testing machine and is vertically arranged, X-direction regulating blocks are symmetrically arranged at left side and right side along X-direction of the mechanics loading module, the front end and rear end of each X-direction regulating block are respectively fixed on the Y-direction regulating blocks, and is capable of respectively being driven by the Y-direction regulating blocks to horizontally slide on a pedestal along the Y-direction back and forth; the operation is easy and has automation function, force and displacement during a loading process can be measured, the coordinate figure, curvature radius and strain value at random point on both surface of the plate during the loading process can be measured, the error of test data is less, and the flexibility requirement of the Bauschinger effect for the plate can be satisfied, so that accurate calibration basis for determining material parameter of Bauschinger effect for the plate can be provided.

The invention discloses an anti-buckling clamping device. The device comprises an outer clamping plate, an inner clamping plate, a spring pressing plate, a spiral spring, a bolt and a nut, an outer state concave part, a left observation concave part and a right observation concave part are arranged on the outer clamping plate, and an outer state concave part is disposed on the inner clamping plate. Meanwhile, the invention further discloses an assembly method of the anti-buckling clamping device, a sample matched with the anti-buckling clamping device is designed, and the invention further discloses a method for eliminating the friction effect of the anti-buckling clamping device. Through the anti-buckling clamping device, the sample and the assembly method of the anti-buckling clamping device, the deformation measurement range of uniaxial compression test can be expanded, the test cost can be reduced, the device is simple and easy to operate, and meanwhile, the test data obtained by the method subverts the traditional cognition of the Bauschinger effect and expands the depth of scientific research on the material, therefore the anti-buckling clamping device has important theoretical and engineering practice significance.

The invention discloses a plate stamping springback control method which comprises the steps: obtaining performance parameters, including a Bauschinger effect material parameter, of a plate; constructing an initial mold profile comprising N grid nodes; inputting performance parameters, carrying out stamping simulation conducted on the plate, and obtaining the stress value of each grid node of theplate before springback and the springback amount of each grid node after springback; determining a potential deformation quantity at each grid node according to the stress value and the Bauschinger effect material parameter; determining a target compensation amount of each grid node according to the potential deformation amount and the springback amount, and compensating the initial mold profileto obtain a target mold profile; and according to the target mold profile, stamping and forming the plate. By means of the control method, the target mold profile meeting stamping springback precisioncontrol can be obtained more quickly and accurately, and the stamping simulation and design efficiency is improved.

The invention discloses a DIC-based Bauschinger effect test sample, fixture and method. First, a tube blank is processed into a small gauge-length sample by wire cutting according to the size; a layerof white paint is uniformly sprayed at a sample gauge-length section; after the paint is dried, uneven black spotted paint is sprayed, a speckle sample is manufactured, and the sample is clamped on the test fixture; an electronic universal test machine and a digital speckle system are opened to set focal length to a focal plane where the sample is located, the aperture size is adjusted to obtaina clear speckle picture, then, a calibration plate is used to calibrate the digital speckle system under the condition; a tensile test under different pre-compressed strain conditions is carried out;and the test data is analyzed to obtain a Bauschinger effect of the material. The small gauge-length sample used in the invention has small deformation area and uniform deformation, and can realize tensile compression stress reverse loading. The test method can efficiently and accurately determine the Bauschinger effect of the thin wall plate/tube material.

The invention belongs to the field of steel materials and manufacturing thereof, and discloses a low-Bauschinger-effect low-strain-aging-effect steel tube and a manufacturing method thereof. The steel tube comprises the following components in percentage by mass: 0.02-0.06% of C, 0.05-0.42% of Si, 1.61-1.99% of Mn, at most 0.020% of P, at most 0.010% of S, at most 0.11% of Nb, at most 0.06% of V, at most 0.05% of Ti, 0.0010-0.0080% of N, at most 0.50% of Cu, 0.60-1.00% of Cr, at most 0.0105 of Ca and the balance of Fe and inevitable impurities. The formula and the manufacturing method are reasonably designed; and the steel tube has low Bauschinger effect and low strain aging effect, and remains well matching of excellent deformability and excellent toughness.

The invention discloses a dynamic uniaxial bidirectional asynchronous loading device and a method thereof. The device comprises a first loading gun, a first waveguide rod, a second waveguide rod and asecond loading gun which are coaxially arranged in sequence. The first loading gun is used for emitting a compressive stress wave; the second loading gun is used for emitting a tensile stress wave; the first waveguide rod is connected with the first loading gun, the second waveguide rod is connected with the second loading gun, and a sample is arranged between the first waveguide rod and the second waveguide rod; the length of the first waveguide rod is greater than that of the second waveguide rod; the first loading gun and the second loading gun generate stress waves at the same time, the compression stress waves generated by the first loading gun are conducted to the sample along the first waveguide rod and conduct compression loading on the sample, and the tensile stress waves generated by the second loading gun are conducted to the sample along the second waveguide rod and conduct tensile loading on the sample. According to the invention, the Bauschinger effect of the material under dynamic loading can be obtained.

The invention discloses a test sample for measuring the Bauschinger effect of a plate. The test sample specifically comprises the plate, two semi-annular grooves and two grooves, wherein the two semi-annular grooves are located in the plate, the two semi-annular grooves are symmetrically arranged, a clamping area is formed between the two semi-annular grooves, and an acting area is formed outside the two semi-annular grooves; the two grooves are located at the joint of the two semi-annular grooves, and the two semi-annular grooves are located at the joint of the two semi-annular grooves; meanwhile, the invention further discloses a testing clamp and a testing method which are matched with the testing sample and used for measuring the plate Bauschinger effect. The test sample and the test fixture disclosed by the invention are simple in structure, and by combining with the test method, the Bauschinger effect test of the plate is simple, efficient, accurate and easy to use.

The invention provides a method for detecting a Bauschinger effect value of a steel plate for a welded pipe, and belongs to the technical field of steel performance detection. The method comprises the following steps: cutting a detection sample from a steel plate for producing the spiral seam submerged arc welding steel pipe; cutting a first sample and a second sample from the flattened detection sample; the first sample is bent at least twice in a three-point bending mode, so that a cylindrical surface with the same radius as the spiral seam submerged arc welding steel pipe is formed in a target area on the first sample; after the first sample is flattened, a first tensile sample is cut from the target area on the first sample; cutting a second tensile sample from the second sample; and performing a tensile test on the first tensile sample and the second tensile sample, and determining the Bauschinger effect value of the steel plate according to a tensile test result. According to the scheme, the cost for detecting the Bauschinger effect value can be reduced.

A Bauschinger effect test fixture that cooperates with a test machine for stretching and compressing materials to perform a Bauschinger effect test on a test piece having a symmetrical configuration with two wide ends and a narrow middle part. The fixture includes two identical split bodies, where each split body has a base provided, longitudinally from a central part to one end of the base, with a limiting groove corresponding to a half of the profile of the test piece. Two sides of the groove are arranged symmetrically with a plurality of threaded through holes and a cover is provided along its central axis with two threaded through holes with which the test piece is pressed tightly by bolts. An end of the cover corresponding to a notch of the limiting groove is provided with a through groove configured for placing a stress ultrasonic detection probe on the test piece.