Introduction: JB-300B/500B Impact Testing Machine is developed strictly according to GB/T 3808-1995. It does impact test to mental material according to GB/T229-1994 and meet requirement of ASTM E23 . The maximum impact energy is 300/500 Joule with a hammer of 150/250 Joule. Dimension of breaking surface of the sample is 10*10mm. It mainly does test to black metal, especially to steel and its alloy. The product theory is to present the different of energy before impacting and after impacting on the degree set, through which we can gain the absorbed skill. The advantage of it could be presented better in the sample test. Main technical parameters: 1Impact energy: 150J/300J, 250J/500J  2Distance from the centre of hammer to impact point:800mm (500J)   750mm(300J) 3Impact Speed: 5.4m/s (500J) 5.2m/s(300J) 4Radius of arc circle of sample branch seat: R1-1.5mm  5Arc circle radius of impact knife: R2-2.5mm  6Test specimen specification: 55*10*10mm  7External dimensions: 2124*600*1340mm 300J  2300*600*1400mm (500J) 8Power: 50Hz 380V 180W (can change) 9Working Condition:  a. Room temperature 10-35°  b. Comparative humidity is not more than 85%  c. Environment of no cauterization medium  d. Ply of the groundsill on which installing tester is not than 150mm or fix tester on the base more than 1400Kg  e. Adjust the level degree of fixing the datum plane on the seat of machine in 0.2/1000