欧洲标准EN_205英文版

欧洲 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 EN_205英文版 EUROPEAN STANDARD EN 205 May 1991 Descriptors: Adhesive, wood, wood product bonding, dimensions, dimensional tolerances, test pieces, tests, tensile tests, shear tests, test atmosphere, determination, adhesive strength. English version Test methods for wood adhesives for non-structural applications Determination of tensile shear strength of lap joints This European Standard was approved by CEN on 1991-05-20. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard 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 Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). 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, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Central Secretariat: rue de Stassart 36, B-1050 Brussels C) 1991. Copyright reserved to all CEN members. Ref. No. EN 205:1991 E Page 2 EN 205:1991 Foreword This European Standard has been prepared by Technical Committee CEN/TC 103 'Adhesives for wood and derived timber products'. In accordance with the CEN/CENELEC Internal Regulations, 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, Sweden, Switzerland and the United Kingdom. Introduction European Standards giving test methods and a common classification with respect to durability classes for wood adhesives will allow considerable improvement in consumer protection and provide greater legal security in any future product liability system with regard to properties guaranteed by the adhesive manufacturer. This standard defines durability classes according to the strength of the adhesive. NOTE: See also IS06237:1987 Adhesives; wood-to-wood adhesive bonds; determination of shear strength by tensile loading IS06238:1987 Adhesives; wood-to-wood adhesive bonds; determination of shear strength by compression loading Dimensions in mm 1 Scope This European Standard describes methods of test for adhesives for wood and derived timber products for the assessment of their resistance to various physical effects. It does not apply to adhesives for structural use nor to the manufacture of particleboard, fibreboard, and plywood. It does not replace specific tests or tests on finished products. The method described in this standard is suitable for the following and other applications: - assessing the usability and quality of adhesives for wood and derived timber products; - classifying these adhesives into durability classes D 1 to D 4 of EN 204; - assessing effects on the bond strength resulting from the bonding conditions chosen, the various conditioning sequences and the treatment of the test pieces before and after bonding; - assessing the bond strength of bonds with thin or thick bond line. 2 Normative references This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. EN 204 Evaluation of non-structural adhesives for joining of wood and derived timber products ISO 554 Standard atmospheres for conditioning and/or testing; specifications 3 Joint components 3.1 Selection of wood 1Prepare two unsteamed, planed, straight-grained beech boards ) (fagus sylvatica L) 130 mm wide (see figure 1), one 5 mm thick, the other (5 + a) mm (where a is the thickness of the bond line). For a thin bond line (a ~ 0,1 mm), use 2 boards of 5 mm thickness. The minimum density 3 of the wood fagus sylvatica L shall be (700 ? 100) kg/m when measured on wood having a moisture content of 12 %. The wood shall be conditioned in accordance with ISO 554: at (23 ? 2)?C/(50 ? 5) % relative humidity or at (20 ? 2) ?C/(65 ? 5) % relative humidity. The length of the panels shall be a multiple of ~ 300 mm, for example ~ 600 mm, and the angle between the growth ring surfaces and the surfaces to be bonded shall be between 30? and 90?. Limit deviations for thickness: ? 0,1 mm. If the behaviour of an adhesive applied in a thick bond line, is to be compared with its behaviour when applied in a thin bond line, care shall be taken that the beech boards for both types of bond are cut from the same piece in the direction of the grain, and one directly after the other. To achieve this, cut the boards in the following order: a 5 mm strip for testing the thin bond line, followed by a 5 mm strip for testing the thick bond line, followed by a (5 +a) mm strip for testing the thin bond line, followed by a (5 +a) mm strip for testing the thick bond line. 1) When using other species of wood, special agreements are required. For a list of suitable species of wood, see annex B of ISO 6238. 3.2 Bonding of the joint components The bonding conditions specified by the adhesive manufacturer shall be used. Prepare boards for use with a thin bond line, and, if the adhesive manufacturer specifies it, also for use with thick bond lines of 0,5 mm or 1,0 mm, as required. 3.2.1 Thin bond lines Bond two 5 mm thick beech boards as shown in figure 2, with the grains running in the same direction. Distribute the pressure uniformly over the bonding surface so that 10 mm thick bonded assemblies are formed. Comply with the processing requirements specified by the adhesive manufacturer, including whether the adhesive is applied to one or both sides, the specific quantity to be applied the open and closed assembly time and the pressing conditions. The pressure applied shall be in accordance with the adhesive manufacturer's instructions and/or information contained in quality standards. Immediately before bonding, prepare the wooden surfaces to be bonded by either planing (the preferred method) or with abrasive paper of 2grain size 150 complying with the FEPA standard ). Do not touch or soil the prepared surface. Indicate in the test report if the surface has been treated in a different way. 2) Federation Europeenne des Fabricants de Produits Abrasifs; FEPA-Standard 43-1984 is available from: a) British Abrasives Federation, Fair Green House, Sawbridgeworth, Herts OM 21 9AJ; b) Fachverband Elektrokorund- und SiliziumkarbidHersteller e. V (FES), KaristraBe 21, D-6000 Frankfurt 1. Page 4 EN 205:1991 3.2.2 Thick bond lines Such tests are carried out in order to test the behaviour of adhesives in thick bond lines, which might be caused by poor fit or by surface irregularities arising from processing techniques. As can be seen from figures 1 and 3, the (5 +a) mm thick board is provided with grooves of depth, a = 0,5 mm or 1 mm and width about approximately 14 mm. Apply the adhesive to the grooved board and work it well into the grooves so that they are completely filled allowing for squeeze-out Bond (5 + a) mm thick grooved boards to 5 mm thick ungrooved boards to obtain (10 +a) mm thick bonded assemblies for the preparation of the test pieces. 4 Test pieces Take five pieces with a width, b = 20 mm from the bonded assemblies according to the location of the cuts as indicated in figure 1 after removing the long edges and identify, e.g. by serial numbers from 1 to 5. After identification (see figure 1), divide into test pieces with a length of l = 150 mm. Make saw cuts in the test 1 assemblies symmetrically about the centre of the lap as shown in figure 3. This defines a test surface with l= 10 2 mm. Take care that the cuts completely cut through the bonding surface of the samples. As thin adhesive joints are only a few hundredths of a millimetre thick, take care that the cuts only penetrate as little as possible into the other part of the joint 5 Conditioning and number of test pieces After bonding the test pieces, condition them. The nature and duration of this conditioning depend on the requirements to be met by the adhesive. The sequences of conditioning are given in table 2 of EN 204. At least 20 test pieces are required for any conditioning or conditioning sequence for each strength test Test the test pieces immediately after the ending of the last conditioning to avoid further changes in the moisture content 6 Tensile shear test At least 1 week shall pass between bonding and testing of the test pieces. This period shall be prolonged if specified by the manufacturer. Test the test pieces shown in figures 2 and 3 in a tensile testing machine. Clamp the ends of the test pieces in the jaws of the tensile testing machine, up to a length of 40 mm to 50 mm. Ensure that the force is applied centrally and in the plane of the bond. Load the test piece until breakage. Determine the maximum force, F max, occurring during this procedure. For comparative tests of adhesives and for assigning an adhesive to the durability classes according to EN 204 conduct the test at a rate of transverse of approximately 50 mm/min. 7 Expression of results The following is applicable to tests according to clause 6: 2The strength , T in N/mm, is calculated according to the following formula: FmaxmaxF T = ,A(.)lb where F max. is the maximum force, in N; A is the bonded test surface, in mm2 l is the length of the bonded test surface, in mm; b is the width of the bonded test surface, in mm. 8 Test report The following items shall be reported: Data about the adhesive: - type and origin of the adhesive; - batch number of the adhesive used; - number of components and working methods (procedure of precoating and mixing); - length of overlap, l; 2 - durability class (for information only). Preparation of the test pieces and testing: - species of wood, with botanic name; - moisture content of wood, relative to oven-dry mass; - characteristic data relating to the bonding procedure (e.g. information about pressing power, pressing temperature, pressing time); - time between the termination of pressing and the cuffing out of the test pieces; - special treatment of the surface of the boards to be bonded; - indication whether test pieces with a thin (0,1 mm) bond line or with a thick (0,5 mm or 1 mm) bond line have been used respectively; - number of test pieces; - conditioning sequences applied (serial number as given in EN 204, table 2); - testing speed. Test results and data about the durability class: 2 - strength, T, in N/mm, rounded to 0,1 N/mm2, i.e. minimum value, maximum value and mean value; 2standard variation, s, in N/mm; - coefficient of variation, V, as a percentage; - appearance of the surfaces of the break; - indication of the estimated portion of wood failure or wood breakage (the indications are to be graded as follows: 0, 25, 50, 75, l00% breakage of wood) as a percentage (mean value for all test pieces); - description of further peculiarities of the appearance of the break; - if necessary, deviations from this standard; - indication of durability class according to EN 204, if required; - date of test Annex A (informative) Single-lap test pieces For in-house tests as well as for quick-setting adhesives single-lap test pieces as shown in figure 4 may be used rather than the test pieces shown in figures 1, 2 and 3. When clamping these test pieces into the tensile testing machine, ensure that the applied force is in the plane of the bond line and centrally applied by using either shims or appropriately designed clamps. Selection and the bonding of the wood should be in accordance with 3.1 and 3.2. When bonding test pieces according to figure 4, it is recommended that two cuts be laid one on top of the other in such a way that the angles of the growth rings run in the opposite direction.