73 results about "Indentation testing" patented technology

Disclosed an indentation testing instrument including: a loading lever supported pivotally; an indenter provided on the loading lever; an indenter linkage section; a loading lever driving section; a reference lever supported pivotally having a same shaft center as the loading lever; an indenter reference section provided on the reference lever as a positional reference of a tip portion of the indenter; an indenter position detection section; a reference lever driving section; a stopper to stop the reference lever; a specimen surface reference measurement member to turn the loading lever from the state that the indenter reference section touches the specimen surface, and to measure a first indentation depth amount; and a machine frame reference measurement member to turn the loading lever from the state that the reference lever touches the stopper and the indenter reference section is spaced apart from the specimen surface, and to measure a second indentation depth amount.

The present invention relates to a method of measuring residual stress and, more particularly, to a residual stress measuring method using a continuous indentation tester. Due to pile-up and sink-in of a material or a blunted tip, a conventional residual stress measuring method cannot compensate for error of a real contact (indentation) depth or directly remove stress through a thermal or mechanical technique in the conventional method of measuring residual stress of a weldment, so that it is very difficult to estimate a stress-free reference curve or to quantitatively measure residual stress. However, the present invention can precisely estimate a stress-free curve of a weldment using an indentation strength ratio (OIT ratio) of a stress-free base metal to the weldment, and compensates for error, occurring in the measurement of a material having a weldment or an anisotropic stress structure, based on the indentation strength ratio, thereby more precisely measuring residual stress. Thus, unlike the conventional method, the present method can minimize error occurring in the residual stress measuring process, and agrees with actual models.

Disclosed a test management method for an indentation tester which includes a control section and forms an indentation on a surface of a heated or cooled sample by pressing an indenter to which a load is applied onto the surface of the sample, the test management method including the steps of: measuring a predetermined reference block as the sample under a plurality of temperature environments to obtain a test result; calculating a test error caused by temperature environment based on the test result by the control section; and judging whether or not the test error is within a predetermined range by the control section.

An indentation testing instrument including: a loading lever supported pivotally; an indenter provided on the loading lever; a displacement sensor movable section; a loading lever driving section; a reference lever supported pivotally having a same shaft center as the loading lever; a contactor provided on the reference lever as a positional reference of a tip portion of the indenter; a displacement sensor fixing section; a reference lever driving section; a stopper to stop the reference lever; a specimen surface reference measurement member to turn the loading lever from a state that the contactor touches the specimen surface, and to measure a first indentation depth amount; and a machine frame reference measurement member to turn the loading lever from a state that the reference lever touches the stopper and the contactor is spaced apart from the specimen surface, and to measure a second indentation depth amount.

The invention discloses a graphene metal composite material prepared through a metal salt precipitation method and a preparation method of the graphene metal composite material prepared through the metal salt precipitation method. The graphene metal composite material is characterized in that metal salt and graphene oxide are used as raw material, through the metal salt precipitation method, the graphene oxide is reduced to be graphene, the meta salt is precipitated to be metal material, and therefore the graphene metal composite material with the metal material as a parent is formed, wherein the flake graphene is inserted into the metal material in an embedded mode. The graphene metal composite material is prepared through the metal salt precipitation method, reaction in-situ is performed on oxygen-containing functional groups on the graphene oxide and metallics obtained through precipitating the metal salt, and a bonding effect is achieved between the metallics and the graphene oxide, so that the flake graphene is not prone to be agglomerated, and the problems that graphene is prone to being agglomerated and poor in dispersity in the parent metal material are solved. Through indentation testing and melting point testing, the hardness of the sample is improved, the melting point of the sample is increased, and performance of the sample is improved.

The invention disclsoes an indentation tester. Indentation tester capable of adjusting vertical-direction positioning drift due to individual differences of an indenter when indenters are switched includes an adjustment mechanism. The adjustment mechanism adjusts relative vertical-direction positions of a displacement sensor movable portion and a displacement sensor fixed portion. The adjustment mechanism includes a first hollow disk having a spiraling surface formed on a bottom surface; and a second hollow disk having a spiraling surface 91 formed on a top surface. The spiraling surfac of the second hollow disk has a thread equal to that of the spiraling surface 91 of the first hollow disk. The first hollow disk rests on the second hollow disk such that the bottom surface of the first hollow disk is overlaid on the top surface of the second hollow disk. The first hollow disk and the second hollow disk are capable of rotation on a center axis of an indenter column.

Indentation tester capable of adjusting vertical-direction positioning drift due to individual differences of an indenter when indenters are switched includes an adjustment mechanism. The adjustment mechanism adjusts relative vertical-direction positions of a displacement sensor movable portion and a displacement sensor fixed portion. The adjustment mechanism includes a first hollow disk having a spiraling surface formed on a bottom surface; and a second hollow disk having a spiraling surface formed on a top surface. The spiraling surface of the second hollow disk has a thread equal to that of the spiraling surface of the first hollow disk. The first hollow disk rests on the second hollow disk such that the bottom surface of the first hollow disk is overlaid on the top surface of the second hollow disk. The first hollow disk and the second hollow disk are capable of rotation on a center axis of an indenter column.