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CHARPY IMPACT TEST
 
charpy impact test  

Charpy Impact Test

Charpy Impact Test.

A test of the impact strength of a material, used to determine its relative ductility or brittleness. The test is executed by swinging a large, heavy hammer on a pendulum from a predetermined height. The hammer fractures the material sample, usually a block of a certain size with a notch cut in it. The height to which the pendulum swings is used to calculate the energy necessary to fracture the sample.

The tester is equipped with a falling pendulum hammer, able to break, with a single blow, a sample carved in the middle and positioned on two supports.
The test is carried out on a CHARPY sample in order to check the energy absorbed during the impact, which is measured in JOULE.
The value stands for the impact strenght of the material ( resilience) .
- Cast iron frame
- Pendulum with hardened knife
- Brake device to stop the pendulum
- Impact energy 300J with 2J graduation
- Falling angle: 140°
- Pendulum mass Kg. 21, 300
- Impact speed: 5, 187 m/ s

 
 
 
 
 
Brand : DBA    
Price : Flexible / Negotiable    
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CHARPY IMPACT TESTING MACHINE

  1. Purpose

The purpose of the charpy impact testing machine lies in measurement on brittleness of metallic materials. The Following is the impact testing procedure. That is, a test piece prepared is supported at both ends and impact force, given to its central part. Then, absorption energy required for breaking the specimen is measured and calculation, made on the charpy impact value.

  1. Capacity and Dimensions

Capacity                                                                                               :               300 Joule
Model                                                                                                   :               Charpy
Weight of Pendulum Hammer (W)                                           :               214,668 N
Length from the axis to the center of percussion (L)        :               0,7500 m
Lifting angle of hammer                                                                :               150,0°
Dimension (LxWxH)                                                                        :               1040 x 800 x 400 mm

  1. Construction

The Unit consist of high precision bearings, a hammer, a dial and a hammer, a dial aand a hammer lifting device at the upper part of a robust frame, a support stand for test specimen at a lower part and hammer stopper at lowermost part.

  1. Pendulum System

A pendulum shaft provided with a hammer is put in the bearing and metal futtings for pointer guide, fixed to its end. The Lifting angle and swinging-up  angle of the hammer are indicated by the pinter. As For the positional energy for impact bending of test specimen, it is not a mere weight of the hammer. It also includes the weight of ball bearings at rotary part of hammer and at both ends of the said shaft. The total value of the metal fittings for pinter guides is the weight for calculation of positional energy. Usually, it is called PENDULUM SYSTEM including them.

  1. Hammer Lifter

The Hammer lifter consist of hammer hook, worm gears and bevel gear handle. This unit has such a constructuin as mentioned hereunder. That is, when the hammer is lifted up or down or under vibration, if it is caught by hook, the hook lever is designed to  be as long as possible in order to prevent impact vibration from being given to the measuring device for energy. As the same time, the vibration given to the worm gears is eliminated by buffer spring installed at the worm shaft.

  1. Measuring device for Energy

The angle dial is graduated eith degrees ranging from 0 to 180° with one degree as unit 1 line, the numerals showing angle are privided every 10 degrees, i. e. 0°, 10°, 20° etc.
The Said numerals are stamped red and black in bith lifting up and swinging-up directions. The said dial is fitted to the worm gear with the pendulum shaft as center. The Pointer showing angle is installed at the shaft center od the dial in such a way that it holds of the plate spring lightly. The lifting angle and swinging-up angle are indicated with the metal fitting for guide for pendulum system.

  1. Support Stand for Test Specimen

The impact part of support stand for test specimens for this unit has been subjected to an annealing treatment. And the frame has been subjected to a groom treatment for attaining Plug-in tightening, its end provided with the metal  fittings for reception of impact. In Conventional types of support stands, if test specimen is broken pieces should strike againts the support stand, resulting is reversal, the hammer will be broken very often. Improvement has been made on this unit and broken pieces fly away toward the outside.

  1. Hammer Stop Device

Hammer stop Device udes disk brake system. When the hammer impacted of the specimen, the pendulum will be moved, for the stop pendulum, push the handle with foot.

  1. Caution For Installation
  2. Complete foundation work must be be done for foundation concrete as instructed according to insatallation drawings for giving impact vibration.
  3. Horizontal must be checked by placing a water level on the receiver stand for test specimen.
  4. Place an attached 10 mm standard gauge on the receiver stand for test specimens and adjust it to the position where the hammer blade contacts lightly.
  5. When the test specimen is broken, broken pieces fly away in the forward direction. Accordingly, install it in such a way the broken pieces fly away in the wall direction.

 

  1. Testing procedure
  2. Inspection Before Test
  3. Apply the position for hammer to the receiver stand for test specimens and check whether or not the hammer is located at normal position. If the blade surface of hammer is not in accord with the gauge groove, loosen the tightening bolts at rotary part of hammer and adjust it to the correct position.
  4. Adjust the inteval of the receiver of the receiver stand for test specimens by means of a position gauge for test specimens. The standard specified is 40 ± 0,2 mm. The gauge has been designed and manufactured in such a range.
  5. Place the 10 mm standard gauge on the receiver stand for test specimens and apply the blade edge of hammer to the gauge. When the pointer is applied to the metal fittings for guide, if the pointer indicateds 0 and 180° vertically, it will be correct. If different, loosen the nuts for metal fittings for gauge and adjust it to the specified position.
  6. Prepare the best specimen and let the notch groove surface the inside of the receiver stand for the test specimen. Insert the position gauge for test specimen between the receiver stands at both sides and places the test specimen un such  a way thet gauge pin is in accord with the notch groove for test specimen.
  1. Impact Energy
  2. Hook the hammer with the hook for hammer lifter
  3. Lift the hammer to the max lifting abgle ( Stopper Position) with the handle. In this case, the pointer must indicate the lifting angle with the guide metal fittigs.
  4. Hold the hook release handle. Drop The hammer the specimen position. After breaking of the test specimen, the swinging-up angle is indicated. The said angle is the satndard for calculation of absorption energy.
  5. AS for energy required for breaking, calculate according to TABLE FOR ENERGY.
  6. As for the energy E required for breaking specified in standard document (BS, JIS, ASTM, etc ) it can be calculated from the following formula :

 

E = M ( 1- cos α )

Where,
             E              =             Energy
             M            =             Momen
                             =             W x L (Nm)
             Α             =             Lifting angle of hammer
With energy as one place, count as one fractions of more than 0,5 inclusive and cut away the rest.

  1. Calculation Of Energy In Attached Table

When the hammer drops from the lifting angle (α), if it goes up to the swinging-up (ф) after breaking of the specimen will be E1-E2. But, in this case, such energy loss and friction or rotary parts, bearing, pointer and air resistance are not include.
E1   =             Positional energy owned by hammer at lifting-up angle (α)
E2   =             Positional energy owned by hammer at swinging-up angle (β)
E1   =             M ( cos – β1 – cos ( α – β1 )
E2   =             M ( cos – β2 – cos ( α – β2 )

 

The aforementioned formula is specified. In this formula, WR and a are in herent values of the testing machine. Accordingly, it si possible to know the energy (E Joule) required for breaking of the specimens from the swinging up angle (β) of hammer. Calibrate the respective testing machine and the value of the energy for one degree up to 150°C of the swinging-up angle are found out and shown in the list. In actual test, the hammer uis made to drop from the specified lifting-up angle (β) is known from the pointer. From the said angle, the energy required for breaking of the test specimen can be known from the list for energy.

CHARPY IMPACT TESTING MACHINE

Capacity                                                                                               =             300 Joule
Length from the axis to the center of presusion                                =             0,7500 m
Lifting angle of Hammer                                                                                =             150,0°
Weight of Pendulum Hammer                                                   =             214,668 N
Momen                                                                                                                =             161,00 Joule
Impact Energy                                                                                   =             -298,275 Joule
Center of percussion                                                                      =             0,7460 m
Speed of hammer at impact                                                        =             5,2 m/sec

Angle
(α)

Energy
(Joule)

 

Angle
(α)

Energy
(Joule)

 

Angle
(α)

Energy
(Joule)

 

Angle
(α)

Energy
(Joule)

1

0,025

 

39

35,880

 

77

124,783

 

114

226,485

2

0,098

 

40

37,667

 

78

127,526

 

115

229,042

3

0,221

 

41

39,492

 

79

130,280

 

116

231,578

4

0,392

 

42

41,354

 

80

133,043

 

117

234,092

5

0,613

 

43

43,252

 

81

135,814

 

118

236,585

6

0,882

 

44

45,186

 

82

138,593

 

119

239,054

7

1,200

 

45

47,156

 

83

141,379

 

120

241,500

8

1,567

 

46

49,160

 

84

144,171

 

121

243,921

9

1,982

 

47

51,198

 

85

146,968

 

122

246,317

10

2,446

 

48

53,270

 

86

149,769

 

123

248,687

11

2,958

 

49

55,374

 

87

152,574

 

124

251,030

12

3,518

 

50

57,551

 

88

155,381

 

125

253,346

13

4,126

 

51

59,679

 

89

185,190

 

126

255,633

14

4,782

 

52

61,879

 

90

161,000

 

127

257,892

15

5,486

 

53

64,108

 

91

163,810

 

128

260,121

16

6,237

 

54

66,367

 

92

166,619

 

129

262,321

17

7,035

 

55

68,654

 

93

169,426

 

130

264,489

18

7,880

 

56

70,970

 

94

172,231

 

131

266,626

19

8,772

 

57

73,313

 

95

175,032

 

132

268,730

20

9,709

 

58

75,683

 

96

177,829

 

133

270,802

21

10,694

 

59

78,079

 

97

180,621

 

134

272,840

22

11,723

 

60

80,500

 

98

183,407

 

135

274,844

23

12,799

 

61

82,946

 

99

186,186

 

136

276,814

24

13,919

 

62

85,415

 

100

188,957

 

137

278,748

25

15,084

 

63

87,908

 

101

191,720

 

138

280,646

26

16,294

 

64

90,422

 

102

194,474

 

139

282,508

27

17,548

 

65

92,958

 

103

197,217

 

140

284,333

28

18,845

 

66

95,515

 

104

199,949

 

141

286,120

29

20,186

 

67

98,092

 

105

202,670

 

142

287,870

30

21,570

 

68

100,688

 

106

205,378

 

143

289,580

31

22,996

 

69

103,303

 

107

208,072

 

144

291,252

32

24,464

 

70

105,935

 

108

210,752

 

145

292,883

33

25,974

 

71

108,584

 

109

213,416

 

146

294,475

I34

27,525

 

72

111,248

 

110

216,065

 

147

296,026

35

29,117

 

73

113,928

 

111

218,697

 

148

297,536

36

30,748

 

74

116,928

 

111

218,697

 

149

299,004

37

32,420

 

75

119,330

 

112

221,312

 

150

300,430

38

34,130

 

76

122,051

 

113

223,908

 

 

 

 
   
   
   
   
 
   
   
   
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