1、CEN ENt2450b 93 3404589 O047116 350 m EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 24506 April 1993 UM: 669.018.25 : 620.173 Descriptors: Powder metallurgy, hard metals, mechanical tests, compression tests, elastic limit, designation English version Hardmetals - Compression test (IS0 4506 :
2、1979) Mtaux-durs - Essai de compression (IS0 4506 : 1979) Hartmetalle - Druckversuch (IS0 4506 : 1979) This European Standard was approved by CEN on 1993-04-02. CEN members are bound to comply with the CENICENELEC Internal Regulations which stipulate the conditions for giving this European Standard
3、the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Centrai Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, Germ
4、an). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, G
5、ermany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1992
6、Copyright reserved to CEN members Ref. No. EN 24506 : 1992 E CEN EN*2450b 93 3404589 0047117 297 Page 2 EN 24506 : 1993 Foreword In 1992, IS0 4506 : 1979 Hardmetals - Compression test was submitted to the CEN Primary Questionnaire procedure. Following the positive result of the CEN/CS Proposal IS0 4
7、506 : 1979 was submitted to the Formal Vote, The result of the Formal Vote was positive. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 1993, and conflicting national standards shall be w
8、ithdrawn at the latest by October 1993. According to the Internal Regulations of CENKENELEC, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain,
9、Sweden, Switzerland and United Kingdom. CEN ENt2450b 93 m 3404589 0047118 I123 m Page 3 EN 24506 : 1993 1 Scope and field of application This International Standard specifies a method of determining the ultimate strength and proof stress of hardmetals under uniaxial compressive loads. 2 Principle Ax
10、ial loading of a test piece, placed between two hardmetal bearing blocks, until the intended deformation occurs or until the test piece fractures. 3 Symbols and designations Symbol Designation Minimum original cross-sectional area with index) Load at proof stress, for example : Load at 0.2 % proof s
11、tress Ultimate load, .e. load at instant of fracture Stress Strain Youngs modulus with index1 Proof stress, for example : 0,2 % proof stress Ultimate compressive strength Unit mm2 N N NI mm2 % N/mm2 NI mm2 N 1 mm2 4 Apparatus The test machine shall be designed and constructed so that loads can be ap
12、plied at a uniform rate and so that, within the measuring range in question, the maximum loading error will be f 1 Yo. The test piece shall be affixed between two well-centred and rigidly secured hardmetal anvils with a hardness not less than 1 600 HV. These contact surfaces shall be perpendicular t
13、o the loading axis and parallel to each other within 0,5 vm/mm. An example of a suitable anvil is given in figure 1. 5 Test piece 5.1 The dimensions of the test piece shall conform to figure 2. The end faces and the cylindrical surfaces of the enlarged ends shall be ground. Other surfaces should not
14、 be ground. (Grinding or polishing may affect the result of the test. 11 1 5.2 The minimum diameter of the test piece shall be measured with an accuracy of k 0.02 mm. 6 Procedure 6.1 Rate of stress increase The rate at which the load is applied shall be as uniform as possible, and any changes in thi
15、s rate shall be made gradually and without shock. The rate shall not exceed 8 o00 N/s, cor- responding approximately to 100 N/(mm2.s). 1 I curacy. Cylindrical test pieces such as those specified in ASTM E9 1977 or USSR TU 45-19 280 78 may be used to obtain results with potentially less di CEN EN+245
16、0b 73 D 3404587 0047119 ObT D Page 4 EN 24506: 1993 6.2 Determination of proof stress 6.2.1 The proof stress, for example the 0.2 % proof stress, is determined according to figure 3. This method is based on the fact, valid for almost all metals, that if a load is removed after the elastic limit, D,
17、has been exceeded, the load-compression curve will follow a linear path that is roughly parallel to the loading curve below the elastic limit. 6.2.2 Determination of proof stress using the graphic in- tersection method is carried out as follows. 6.2.2.1 keep the test piece positioned properly in the
18、 machine. Apply a pre-load not greater than that required to 6.2.2.2 Determine the stress-strain curve. NOTE - Because of the shortness of the test zone and the hardness of the material, practical difficulties are involved in measuring changes in length using displacement gauges of the clamp-on type
19、 iexten- someted. It is therefore recommended that changes in length be measured using a resistive strain gauge. Two or four gauges should be applied symmetrically at the centre of the test zone. The active length of the gauges should not exceed 8 mm. The results obtained represent an average of the
20、 change in length of the test zone. 6.2.2.3 On the graph thus plotted (figure 31, make OB equal to the specified residual strain (offset), and draw a line BA from B parallel to OC. Ordinate F, of. intersection point Q has the value Fcq and represents the load that corresponds to the proof stress. It
21、 is sometimes difficult to ascertain the direction of line OC from a graph; in such a case, this line can be drawn on the basis of an agreed value of the Youngs modulus. 6.2.3 The proof stress Rcq, in newtons per square millimetre, is given by the formula 6.3 Determination of ultimate compressive st
22、rength 6.3.1 Load the test piece to fracture. 6.3.2 The ultimate compressive strength R, in newtons per square millimetre, is given by the formula FC“ so Rcm =- 7 Expression of results Report the arithmetical mean of at least five determinations, rounded to the nearest 10 N/mm2. 8 Test report The te
23、st report shall include the following informations : a) reference to this International Standard; b) all details necessary for identification of the test piece; c) the result obtained; d) all operations not specified by this International Stan- dard, or regarded as optional; e) details of any occure
24、nce which may have affected the result. CEN EN*2450b 73 3404587 0047120 881 Page 5 EN 24506 : 1993 i, OJ Figure 1 - Suitable hardmetal anvil V 1 V % 1 G$ i 42 f i I Figure 2 - Test piece (The 25 Co-ordinates u to y are at 1 rnrn intervals CEN ENu2450b 93 = 3404589 0047l12L 718 Page 6 EN 24506 : 1993 B A C Figure 3 - Load-compression curve
