NJBST Co.,Ltd.
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
对接焊缝射线检测工艺规程
CONTROLLED 在控本□
UNCONTROLLED 非在控本□
COPY NO 副本编号：
PREPARED BY 编制： DATE 日期：
REVIEWED BY 审核： DATE 日期：
APPROVED BY 批准： DATE 日期：
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
1. General
1.1 This procedure is applied to the x-ray radiographic examination of butt welds for pressure vessels constructed in accordance with ASME Code Section Ⅷ Div1.
1.2 This procedure shall be supplemented, when necessary, with the examination instructions defining more specific variables, which will be prepared by NDE Level Ⅲ personnel.
2. Qualification of Examination Personnel
2.1 Any person engaged in the radiographic examination shall be qualified and certified as a radiographic examiner in accordance with NJBST Co., Ltd.’s “Written Practice for NDE Personnel Training, Examination, Qualification and Certification”(NO.: QCD-011).
2.2 The NDE LevelⅠshall receive the necessary instruction or supervision from a certified NDE LevelⅡ or LevelⅢ Examiner. The NDE LevelⅡ shall receive the instruction or supervision from a NDE Level Ⅲ Examiner.
2.3 According to the respective responsibility range, all examiners shall complete the examination conforming to the referencing ASME Code Sections, standards and written instructions. They shall assure the working quality.
3. Equipment , Tools and Materials
The LevelⅡExaminer shall select the equipment, tools and materials to assure that they are in compliance with the following conditions and the requirement of the examination instruction.
3.1 One of the x-ray equipment shall be selected from Table 1.
Table 1
1. 概述
1.1 本工艺规程适用于按ASME 规范第Ⅷ卷第Ⅰ册要求制造的压力容器的对接焊缝的x射线照相检测。
1.2 必要时，本工艺规程应由探伤作业指导书进行补充以
规定
关于下班后关闭电源的规定党章中关于入党时间的规定公务员考核规定下载规定办法文件下载宁波关于闷顶的规定
更详细的变量，此指导书由NDE Ⅲ 级人员编制。
2. 检测人员资格
2.1从事射线探伤的检测人员必须按南京宝色钛业有限公司的<
>(文件号：QCD-011)进行资格考核评定。
2.2 NDEⅠ级须接受合格的Ⅱ级或Ⅲ级必要的指导或监督。NDEⅡ级须接受NDE Ⅲ 级的指导或监督。
2.3 根据各自的职责范围，所有检测人员应按ASME规范有关卷，标准和作业指导书进行检测并保证工作质量。
3.设备、器材
Ⅱ级人员所选用的设备、器材应能保证符合下列条件和探伤作业指导书的要求。
3.1 X射线设备应从
表
关于同志近三年现实表现材料材料类招标技术评分表图表与交易pdf视力表打印pdf用图表说话 pdf
1中选用。
Type
Mfr.
Max. Tube
Voltabe(KVp)
Max. Tube
Current(mA)
Foc. Size
(mm)
Permitted max. material thick(mm)
Steel
Ti
Zr
xx-2505
Beijing
250
5
2 x 2
38
63
22
xx-3005
Dandong
300
5
1.0 x 2.3
46
70
28
表 1
类型
制造厂家
最大管电压
KVp
最大管电流
mA
焦点尺寸
(mm)
允许的材料最大穿透厚度mm
Steel
Ti
Zr
xx-2505
北京
250
5
2 x 2
38
63
22
xx-3005
丹东
300
5
1.0 x 2.3
46
70
28
3.2 Film
Film selection shall be in accordance with SE-1815, Standard Test Method for Film Systems for
3.2 胶片
胶片须根据SE-1815工业射线照相的胶片系统分类的标准测试方法来选择。胶片分类表应由胶片制造厂提供。胶片
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
Industrial Radiography. The classification table of film shall be provided by the film manufacturer. Film system classes Special, Ⅰ,Ⅱ,Ⅲ,W-A, and W-B are permitted. Depending on the x-ray penetration thickness, a suitable film shall be selected. When using two films method, two different types of film shall be selected.
3.3 Screen
A suitable lead screen shall be selected from Table 2.
Table 2
系统分为特殊、Ⅰ,Ⅱ,Ⅲ,W-A,和W-B。应根据X射线穿透厚度，选择合适的胶片。采用双片法时，应选用两种不同类型的胶片。
3.3 增感屏
从表2中选择适当的铅增感屏。
表2
Tube Voltage
Thickness of lead Screen(mm)
管电压
铅增感屏厚度(mm)
Front
Back
前 屏
后 屏
<150kv
150kv~300kv
0.01~0.03
0.025~0.10
>0.05
>0.05~0.10
<150kv
150~300kv
0.01~0.03
0.025~0.10
>0.05
>0.05~0.1
3.4 Densitometer and Step Wedge Film
The digital densitometer listed in Table 3 shall be used for judging radiograph density. The densitometer shall be checked against a calibrated step wedge film at least once every 90days by the NDE Level Ⅱor ⅢExaminer. The step wedge film shall be calibrated once every 12months by the National Bureau of Standards.
Table 3
3.4 黑度计和阶梯黑度片
用表3 列出的数码黑度计测定射线底片密度。黑度计至少每90天由NDEⅡ 级或Ⅲ级用校验过的阶梯黑度片校验一次。黑度片须至少每12个月由国家标准局校验一次。
表 3
Type
Manufacturer
Mea., Range
Mea., Precision
型号
制造厂
测量范围
测量精度
TD-210
ZHEJIANG
ZHENGHAI
0.00-4.00D
±0.03D
TD-210
浙江瓯海
0.00-4.00D
±0.03D
3.5 Image Quality Indication(IQI)
3.5.1 Type and material of IQIs
3.5.1.1 The wire type IQI presented as Fig. 1 and Tab.4 be used. The wire type IQI shall be manufactured and identified in accordance with the requirements in SE-747.
3.5.1.2 The wires shall be fabricated from material or alloy with same or less radiation absorption than the material being radiographed.
3.5 象质计(IQI)
3.5.1 象质计类型和材料
3.5.1.1应使用线型象质计(图1和表4)。线型象质计的制造和标识应符合SE-747的要求。
3.5.1.2 金属丝的材质应与被透检材料相同，或其射线吸收小于被检材料。
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
Fig 1 图1
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
Table 4 Wire IQI Designation, Wire Diameters and Wire Identity in. (mm)
Table 4 IQI Sets and wire Diameter
表4 线型IQI标识和线径
表4象质计组别和线径
Wire Diameters in. (mm)
线径英寸(毫米)
Set A
Wire No.
Set B
Wire No.
A组
线号A
B组
线号B
0.0032(0.08)
1
0.010(0.25)
6
0.0032(0.08)
1
0.010(0.25)
6
0.004(0.1)
2
0.013(0.33)
7
0.004(0.1)
2
0.013(0.33)
7
0.005(0.13)
3
0.016(0.4)
8
0.005(0.13)
3
0.016(0.4)
8
0.0063(0.16)
4
0.020(0.51)
9
0.0063(0.16)
4
0.020(0.51)
9
0.008(0.2)
5
0.025(0.64)
10
0.008(0.2)
5
0.025(0.64)
10
0.010(0.25)
6
0.032(0.81)
11
0.010(0.25)
6
0.032(0.81)
11
Set C
Wire No.
Set D
Wire No.
C组
线号C
D组
线号D
0.032(0.81)
11
0.100(2.5)
16
0.032(0.81)
11
0.100(2.5)
16
0.040(1.02)
12
0.126(3.2)
17
0.040(1.02)
12
0.126(3.2)
17
0.050(1.27)
13
0.160(4.06)
18
0.050(1.27)
13
0.160(4.06)
18
0.063(1.6)
14
0.200(5.1)
19
0.063(1.6)
14
0.200(5.1)
19
0.080(2.03)
15
0.250(6.4)
20
0.080(2.03)
15
0.250(6.4)
20
0.100(2.5)
16
0.320(8)
21
0.100(2.5)
16
0.320(8)
21
3.5.2 IQI Selection
3.5.2.1 The designated essential minimum wire diameter shall be as specified in Table 5
Table 5 IQI SELECTION 表5 象质计选用
3.5.2 IQI 选用
3.5.2.1 应显示的最小线径必须按表5规定。
Nominal single-wall Material Thickness Range, in(mm)
单壁标称材料厚度范围
in(mm)
Source Side IQI射源侧IQI
Film Side IQI 胶片侧IQI
Essential Wire
Diameter
应显示的线径
in (mm)
Wire No.
线号
Essential Wire
Diameter
应显示的线径
in (mm
Wire No.
线号
Up to 0.25, incl. ≤0.25(≤6.4)
0.008(0.2)
5
0.006(0.16)
4
Over 0.25 thr.0.375 > 0.25~0.375(>6.4~9.5)
0.010(0.25)
6
0.008(0.2)
5
Over 0.375 thr.0.5 >0.375~0.5(>9.5~12.7)
0.013(0.33)
7
0.010(0.25)
6
Over 0.5 thr.0.75 > 0..5~0.75(>12.7~19.1)
0.016(0.4)
8
0.013(0.33)
7
Over 0.75 thr.1.00 > 0.75~1.00(>19.1~25.4)
0.020(0.51)
9
0.016(0.4)
8
Over1.00thr.1.50 >1.00~1.50(>25.4~38.1)
0.025(0.64)
10
0.020(0.51)
9
Over 1.50 thr.2.00 > 1.50~2.00(>38.1~50.8)
0.032(0.81)
11
0.025(0.64)
10
3.5.2.2 For welds with reinforcements, the thickness on which the IQI is based is the nominal single wall thickness plus the estimated weld reinforcement not to exceed the maximum permitted by the SectionⅧDivision 1. For welds without reinforcements, the thickness on which the IQI is based is the nominal single wall thickness. In both cases backing rings or strips shall not be considered as part of the weld thickness in IQI selection.
3.5.3 Placement of IQIs
3.5.3.1 The IQI(s) shall be placed on the source side of the part being examined. When configuration or size prevents placing the IQI(s) on the part or weld, the IQI(s) may be placed on a separate block in compliance with para. T-277.1 of Section V. The separate block shall be placed as close as
3.5.2.2 对有余高焊缝，象质计放处的厚度是标称单壁厚度加上不超过第Ⅷ卷第一分册中允许的焊缝 最大余高估计值。没有余高的焊缝，象质计放处的厚度是标称单壁厚度。在以上两种情况下，衬环或衬带均不作为焊缝厚度的一部分来考虑。
3.5.3 象质计的放置
3.5.3.1 象质计必须放在被检工件的射线源侧。当透照布置或结构尺寸妨碍象质计放在工件或焊缝上时，象质计可放在一个单独的试块(符合ASME第Ⅴ卷T-277.1要求)上。此试块的放置应
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
possible to the part being radiographed.
3.5.3.2 Where inaccessibility prevents hand placing the IQI(s) on the source side, the IQI(s) shall be placed on the film side in contact with the part being examined. A lead letter “F” shall be placed adjacent to or on the IQI(s).
3.5.3.3 The IQI(s) shall be placed on the weld so that the length of the wires is perpendicular to the length of the weld. The identification number(s) and , when used, the lead letter “F” shall not be in the area of interest, exept when geometric configuration makes it impractical.
3.5.4 Number of IQIs
3.5.4.1 When one or more film holders are used for an exposure, at least one IQI image shall appear on each radiograph.
3.5.4.2 If the density of the radiograph anywhere through the area of interest varies by more than minus 15% or plus 30% from the density adjacent to the designated wire of a wire IQI, within the minimum/maximum allowable density ranges specified, then an additional IQI shall be used for each exceptional area or areas and the radiograph retaken.
3.5.4.3 For cylindrical components or spherical components where the source is placed at the center of the component for a single exposure, at least three IQIs, spaced approximately 120deg. apart, are required.
3.5.5 IQI Sensitivity
Radiography shall be performed with a technique of sufficient sensitivity to display the essential wire of a wire IQI, which is essential indication of the image quality of the radiograph. The radiographs shall also display the identifying numbers and letters. If the essential wire do not show on any film in a multiple film technique, but do show in composite film viewing, interpretation shall be permitted only by composite film viewing.
3.6 “B” Mark
A lead symbol “B”, with minimum dimensions of 13mm in height and 1.6mm in thickness, shall be attached to the back of each film holder during each exposure to determine if backscatter radiation is exposing the film.
3.7 Location Markers
The image of the location markers for the coordination of the part with the film shall appear on the film without interfering with the interpretation, with such an arrangement that is evidence that complete coverage was obtained. Location markers shall be placed on the part, not on the exposure holder/cassette.
3.7.1 Single-Wall Viewing
(a) Source Side Markers. Location markers shall be placed on the source side when radiographing the following:
(1) flat components or longitudinal joints in cylindrical or cornical components will be according to Fig. .2.
尽可能靠近被检的工件。
3.5.3.2 用手无法将象质计放在射源 一侧时，象质计可放在与被检工件接触的胶片侧。此时应在象质计上面或附近放一个铅字“F”。
3.5.3.3 象质计放在焊缝上，应使线长与焊缝 长度方向垂直。
3.5.4 象质计的数量
3.5.4.1 一次曝光使用一个或多个胶片暗盒时，每张底片上应至少有一个象质计的影像。
3.5.4.2 若有效评定区内任一处的底片黑度超过线型象质计应显最细丝附近黑度的-15%或+30%，即使在规定的最小最大允许黑度范围内，仍应在每一超标区域增加一个象质计，重新摄片。
3.5.4.3 对于圆筒状部件及球状部件，射线源放在部件中心位置时，进行一次曝光，在工件上至少放三个象质计，且要求大约每1200放一个。
3.5.5 IQI 灵敏度
射线照相方法应有足够灵敏度，要显示出线型象质计应识别线径。射线底片也应显示出识别数码和字母。若多胶片法中的任何一张底片上均未显示出应显线径，但可用叠 合观察法显示出来。
3.6 “B”标记
每个胶片暗盒后背应贴附一个至少高13mm，厚1.6mm的铅标记“B”，以验证曝光过程中是否有背散射作用到胶片上。
3.7 定位标记
用于确定工件布片位置的定位标记，其影象应出现在胶片上，且不得妨碍评片，以此证明透检范围已完全覆盖。定位标记应放在工件上，而不能放在暗袋或暗盒上。
3.7.1 单壁成像法
(a) 射线源侧标记，透照下列工件时，定位标记须放在射源侧：
(1) 平板焊缝，圆筒或圆锥形工件纵缝，见图2。
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
Source side marker
射源侧标记
D: Source to material distance
t: thickness of workpiece
Fig. 2
D
t
D: 射源至工件距离
t: 工件厚度
图2
(2) curved or spherical components whose concave side is toward the source and when the “source-to-material” distance is less than the inside radius of the component;
(3) curved or spherical components whose convex side is toward the source.
(b) Film Side Markers.
(1) Location markers shall be placed on the film side when radiographing either curved or spherical components whose concave side is toward the source and when the “source-to-material” distance is greater than the inside radius.
(2) As an alternative to source side placement in 3.7.1(a), location markers may be placed on the film side when the radiograhp shows coverage beyond the location markers to the extent demonstrated by Fig.3，ie
Leff = (x + Mf + x)。
(2) 弯曲面或球面工件，其凹面朝着射线源，当“射源至材料”距离小于工件内半径时；
(3) 弯曲面或球面工件，其凸面朝着射线源。
(b) 胶片侧标记
(1) 当透照凹面朝射源的曲面或球面工件，且“射源至材料”的距离大于工件内半径时，定位标记应放在胶片侧。
(2) 定位标记不按3.7.1(a)放在射源侧而放在胶片侧时，要求底片上显示的有效范围超过定位标记之外一定长度(见图3，即
Leff = (x + Mf + x)。
定位标记
Location marker
D
t
x Mf x
Fig. 3 图3
x= (t / D) (Mf / 2)
x= additional required coverage, beyond film side location marker
t= component thickness
Mf= film side location marker interval
D= source to component distance
x= (t / D) (Mf / 2)
x:在胶片定位标记两侧要求附加覆盖范围
t ：工件厚度
Mf ：两胶片侧定位标记之间的间距
D：射源至工件表面距离
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(c) Either Side Markers.
Location markers may be placed on either the source side or film side when radiographing either curved or spherical components whose concave side is toward the source and the “source-to-material” distance equals the inside radius of the component.
3.7.2 Double-wall viewing, at least one location marker shall be placed on the source side surface adjacent to the weld (or on the material in the area of interest) for each radiograph.
3.8 A system shall be used to produce permanent identification on the radiograph traceable to the contract, component, weld seam, or part numbers， as appropriate. On the radiograph, the following shall be plainly and permanently included and in any case this information shall not obscure the area of interest.
(1) NJBST (Co name) (2) Job No.
(3) Weld seam No. (4) Radiograph No.
(5) Repair mark, if applicable
(6) Location markings
(7) Thickness of base material
(8) Date of radiography
3.9 Facilities for Viewing of Radiographs
3.9.1 Illuminator used to view radiographs shall be verified that it has sufficient intensity to be visible for the essential wire diameter of IQI and can diffuse the light uniformly. When the radiograph is smaller than the viewing portion of illuminator or will include low density areas, the masks shall be provided to exclude any extraneous light.
3.9.2 In order to obtain the necessary brightness through the radiograph at least 30cd/m2, the viewing equipment shall have the following illumination:
Table 6
(c) 两侧均可标记
射线照曲面或球面工件，其凹面朝着射源，且“射源至工件”距离等于工件内半径时，则标记可放在射源侧，也可以放在胶片侧。
3.7.2 双壁成像法
双壁成像时，在射源侧表面焊缝附近(或在有效区工件上)至少放一个定位标记。
3.8 标识
底片上应有永久标识，即合同号、部件号、焊缝号或工件号等。
下列永久性标识应明确无误地显示在底片上，且不得干扰有效评定区。
(1) 南京宝色钛业有限公司(NJBST)；
(2) 工件号；
(3) 焊缝号 (4) 底片号；
(5) 返修标记；
(6) 定位标记；
(7) 母材厚度；
(8) 透照日期；
3.9 观片设备
3.9.1 必须校验观片设备灯是否有足够的光强观看象质计应显线径，能否均匀地扩散灯光。当底片小于观片灯屏尺寸或存在低黑度区域时，应遮档多余光线。
3.9.2 为使底片透过光强至少为30cd/m2,观片灯应有表6所示照明亮度。
表 6
Radiograph Density
Minimum Illumination
底片黑度
最小照明亮度
2.0
3,000cd/m2
2.0
3，000 cd/m2
3.0
30,000 cd/m2
3.0
30，000 cd/m2
4.0
300,000 cd/m2
4.0
300，0000 cd/m2
3.10 Viewing Room
Subdued background lighting shall be provided such that the intensity shall not cause troublesome reflection, shadows or glares on the radiograph.
4. Check of Surface to be Radiographed
Prior to starting of radiographic examination, the
3.10 观片室
应提供柔和的背景光线，光线亮度不得在底片上产生有干扰作用的反射、阴影或眩光。
4. 被检表面检查
射线透照检测前，RT人员必须
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Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
Examiner shall check or verify that the surface to be radiographed satisfies the following conditions:
4.1 The reinforcement of butt welded joints is within the value specified in Section Ⅷ Division 1 as shown in Table 7
Table 7 表7
检查或验证被检表面是否满足下述条件：
4.1 对接焊缝余高应在第Ⅷ卷第1分册规定的数值内。
Nominal
Thickness,in.(mm)
Maximum Reinforcement,in. 最大余高in,(mm)
Category B & C Butt welds
B 和C类对接焊缝
Other Welds其它焊缝
Less than 3/32(<2.4)
3/32(<2.4)
1/32(0.8)
3/32 to 3/16, incl. (2.4~4.8)
1/8(3.2)
1/16(1.6)
Over 3/16 to 1/2,incl. (>4.8~12.7)
5/32(4.0)
3/32(2.4)
Over 1/2 to 1,incl. (>12.7~25.4)
3/16(4.8)
3/32(2.4)
Over 1 to 2,incl. (>25.4~50.8)
1/4(6.4)
1/8(3.2)
Over 2 to 3,incl. (>50.8~76.2)
1/4(6.4)
5/32(4.0)
Over 3 to4,incl. (>76.2~101.6)
1/4(6.4)
7/32(5.5)
Over 4 to 5,incl. (>101.6~127)
1/4(6.4)
1/4(6.4)
Over 5(>127)
5/16(7.9)
5/16(7.9)
GENERAL NOTES:
(a) For double welded butt joints, this limitation on reinforcement given above shall apply separately to both inside and outside surfaces of the joint.
(b) For single welded butt joints, the reinforcement limits given above shall apply to the outside surface of the joint only.
(c) Thickness of weld reinforcement shall be based on the thickness of the thinner of the materials being joined.
(d) The weld reinforcement thickness shall be determined from the higher of the abutting surfaces involved.
(e) Weld reinforcement may be removed if so desired.
4.2 Any surface irregularities, such as weld ripples, splashing, undercut and surface roughness, cannot mask or be confused with the image of any discontinuity.
5. Setup for Exposure
Level Ⅰor levelⅡ individual shall set up the equipment, tools and materials for exposure in accordance with the examination instruction so all requirements for radiograph will be met. The setup information shall be truly and clearly recorded as described in paragraph9.
5.1 Arrangement of Film. IQI and Markers.
5.1.1 Film cassette, IQI and markers shall be placed in accordance with Fig. 4. The Examiner who performs the exposure shall carefully insert the specified film into cassette and attach the “B” mark on its back.
注：
a. 对双面对接焊缝 ，上列余高限值对焊缝内外两面均适用。
b. 对单面对接焊缝上列余高限值仅适用于焊缝外面 。
c. 焊缝余高高度应按被焊接工件较薄厚度取值。
d. 焊缝 余高高度应从对接表面的较高处定值。
e. 视需要，可去除焊缝 余高。
4.2 任何表面不规则状态，如焊波，飞溅、咬边、表面粗糙度，不得掩盖缺陷影象或与之相混淆。
5. 透照布置
Ⅰ级和Ⅱ级人员应该根据探伤作业指导书布置透照的设备，器材，使之满足射线照相的所有要求。应按9要求正确
记录
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布置数据。
5.1 胶片，象质计和标记的安放
5.1.1 胶片暗盒，象质计和标记应按图4放置。曝光操作者应将指定的胶片仔细插入暗盒，并在暗盒后背面贴上“B”标记。
5NJBST Co.,Ltd.
QCD-012
Rev.:0
Page:10 of 17
Title: RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS
1. Location marker
2. NJBST (Co. Name).
3. Job No.
4. Weld seam and radiograph No.
5. Repair and time marker
6. Location marker.
7. IQI
8. Date of radiography
9. Thickness of base material
10. “B” mark
11. X-ray machine
12. Film
13. Back scattered radiation shield
5.1.2 If the density of the radiograph anywhere through the area of interest varies by more than –15% or +30% from the density adjacent to the designated wire of a wire IQI within the minimum and maximum allowable density ranges specified in Table8, then two IQIs shall be used. One shall be placed on the lightest area of interest and the other shall be placed on the darkest area of interest.
Table 8 Acceptable Min &Max Density.
1. 定位标记
2. 南京宝色钛业有限公司(NJBST)
3. 工件号
4. 焊缝号片号
5. 返修标记及次数标记
6. 定位标记
7. 象质计
8. 透照日期
9. 母材厚度
10. “B”标记
11. X射线机
12. 胶片
13. 背散射屏蔽板
5.1.2 射线底片有效评定区内任一点的黑度，大于指定要显示的象质计金属丝附近黑度-15%或+30%时，尽管此黑度落在表8规定的范围内，还是应使用两个象质计。一个放在有效区的黑度最小区，另一个放在有效区的黑度最大区。
表8合格的最小和最大黑度
Method of Viewing
Density of Radiograph
观片方法
D
Minimum
Maximum
Min.
Max.
Single
1.8
4.0
单 片法
1.8
4.0
Composite
1.3△
4.0
双片法
1.3△
4.0
△Each radiograph of a composite set shall have a minimum density of 1.3.
5.2 Geometric Condition for Exposure.
5.2.1 Minimum source-to-object distance and maximum distance from source side of object to the film shall meet the requirements of geometric unsharpness (Ug). The geometric unsharpness of radi
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