SU875258A1 - Method of evaluating stampability of metal on the base of iron - Google Patents

Description

The invention relates to the field of strength of materials and, in particular, to methods for evaluating the stampability of an iron-based material. A known method for assessing the stamping of a material is that a sample of a material is placed on a matrix, its peripheral part is pressed by a clamp, and the central part is loaded with a metal punch until the sample fl is destroyed. The disadvantages of this method are its narrow test ranges due to the inability to create any given stress state and high material intensity. The closest to the invention in technical essence and the achieved result is a method for assessing the formability of an iron-based material, which consists in the fact that risks, initial length, width and thickness of the working part of the sample are applied to the working part of the sample, load the sample to the specified loads, corresponding to yield stress and above them, unloading: the sample, measure the length, width and thickness of the working part of the sample after unloading, bring the sample and its destruction, make a microsection and determine the amount of interferon ferrite points and n & lttlet score 2. The disadvantage of this method is its low accuracy and reliability, since n & n does not take into account all factors affecting stampability, for example, the ability of a metal to evenly distribute plastic deformations, etc. .. The purpose of the invention is to improve the accuracy and reliability of the method. This goal is achieved by the method determining the total score of nonmetallic inclusions, choosing the part of its uniform elongation over the most part of the broken sample, determining the number of scratches on this site,

which calculate the initial length of this section, measure the final length,

shirshsha and thickness. of this area,

and about the strain- / poyteem judged by the formula

F-Circuits. F-O- (5.u - ((5.HB-i) where F is a complex criterion stamped MOCTHJ QO initial thickness of the working part of the sample; Initial width of the working part of the sample; initial length of the working part of the sample; initial length of the section of uniform elongation the sample; the thickness of the working part of the sample after the intermediate load; the width of the working part of the sample after the intermediate load; the length of the working part of the sample after the intermediate load; the final thickness of the sample in the area of uniform elongation the final width of the sample in the area of uniform elongation uniform elongation of the specimen after rupture; load when the yield point is reached; intermediate load; maximum load before the specimen is destroyed; the number of adjacent ferrite points; 6.C.ce., cementite; 6.NV.The total score of non-metallic inclusions. performed as follows

her 1 JiaoK boK

O.fiixuDm1 ((

RbSilmRog) 2 (su. Y.u- (J.H.B-i j OoHo3

The proposed method for determining the strain strain, as well as mutual computability, takes into account the plasticity of the material, which is uniformly relative to the formability of different properties of the metal elongation, the ability of the metal to the metal, allows very accurately and reliably For a uniform distribution of plasticity, the ability of the sheets to be stamped. A tensile test material is made from an experimental iron-based material. On the working part of the sample material is applied at regular intervals risks. The initial length KO is measured. width 1oo and thickness O about the working part of the sample. Place the sample in the grips of the testing machine and load the sample with a tensile force up to the load P | , exceeding the yield strength of the material. In this case, a loading diagram is written to obtain the values of the load Pd corresponding to the physical or conventional yield strength of the material. Unload the sample. The length of the BQP, the width LOP and the thickness OOP of the working part of the specimen after the unloading are measured. Again, the sample is loaded until it is destroyed, while the greatest load P is fixed on the sample before it is destroyed. For the most part of a broken sample, a section of its uniform elongation (for example, a section with the same increase in the distance between risks) is selected, the number of scratches in this area is chosen, from which the initial length of the orc of this section is calculated, the final side length is curved, the width Qb is the thickness QQ plot. A microsetiff is made from the sample and the standard methods are used to determine the number of adjacent points (b.f.) of ferrite, score (b.C. Cementite, and total score (b.v. non-metallic inclusions). Then determine the material compatibility by formula

f

formula of invention

The method for assessing the scalability of a mat on the basis of scabs, consisting in that the working length of the sample, measuring the initial length, width and thickness of the working portion of the sample, loads the sample to the specified loads corresponding to yield stresses and above them, unloads the sample. , measure the length, width and thickness of the working part of the sample after unloading, bring the sample to fracture, make where F is the complex criterion of compressibility; QQ is the initial thickness of the working part of the sample; Q - initial width of the working part of the sample; BO is the initial length of the working part of the sample; СОР - the initial length of the section of the non-dimensional UDLINING of the sample; Qp-p is the thickness of the working part of the sample after intermediate loading; the width of the working part of the specimen, after an intermediate load, is the length of the working part of an end-face after the intermediate load; - final sample thickness on the section of uniform elongation;

875258

microscopic |) and determine the number of adjacent ferrite glands and cementite score, characterized in that, in order to improve the accuracy and reliability of the assessment, the score of nonmetallic inclusions is additionally determined, a portion of its uniform elongation is selected on most of the broken sample, In this area, from which the initial length is calculated, the final length is measured (to the Schfin and the thickness of this section), and about the trial court g, using the OK formula, the width of the section at the section is the elongated length & ka uniform sample elongation after fracture; -load when the yield point is reached; -computable load; -the greatest load, sample destruction, b, f., - the number of adjacent ferrite points; -call cementite; nv-total score of nonmetallic inclusions Sources of information that are taken into account in the examination. V. Kukhtarov. Cold stamping, Ashgiz, 1956, pp. 12-13 ... GOST 9045-7О (prototype).

Claims (1)

Claim A method for assessing the stampability of an iron-based material, which consists in the fact that risks are applied to the working part of the material sample, the initial length, width and thickness of the working part of the sample are measured, the sample is loaded to predetermined loads corresponding to yield strengths and above them, the sample is unloaded, the length is measured , the width and thickness of the working part of the sample after unloading, bring the sample to fracture, make microslug and determine the number of adjacent points of ferrite and cementite score, characterized in that, in order to increase the accuracy and reliability of the assessment, they additionally determine the total score of non-metallic inclusions, select the portion of its uniform elongation on “the greater part of the torn specimen, determine the number of patterns in this section, which calculate its initial length, measure the final length, width and thickness of this section, and g and judged by the formula Eg 1 Ook Lok ’° op L ' 1¾ Eqk “top. _Pg_ <= op ° ^U Ooo ---------------------------------> - a comprehensive criterion for stampability; - the initial thickness of the working part of the sample; 25 - the initial width of the working part of the sample; - the initial length of the working part of the sample; With _О p - the initial length of the plot is equal to the number extension of the sample; 0 _οη is the thickness of the working part of the sample after intermediate loading _t ; L _Op - the width of the working part of the sample after an intermediate load; ΒθΡ is the length of the working part of the sample after an intermediate load; - final thickness of the sample in the area of uniform elongation; "about B Bok the final width of the sample in the area of uniform elongation; θορκ “the length of the section of uniform elongation of the sample after fracture; - load when yield strength is reached; - intermediate load; - the greatest load before the destruction of the sample; - the number of 'adjacent points of ferrite; - cementite score; P ₅ b. c. b.n.v. - total score of non-metallic inclusions.