where 0 represents the angle of contact (Figure I). From
the point of view of the liquid penetrant test, 0 and cr are
affected by the characteristics of the materials tested. If
the Ii uid completely wets the surface 19 can be taken as
zeroI
The above-mentioned conditions represent the surfaces
of the materials, but inside the defects the roughness of
the walls is very different.
For capillarity, rising energy is needed to reverse the
tendency towards reduction of surface area in liquids.
Surface tension is the energy required to increase the
surface area of a liquid by a unit amount. Thus, the
height to which the liquid rises is determined by the
surface tension and the weight of the liquid column[7581.
Liquid is not pulled up by capillarity; it is pushed up by a
pressure difference. There is always a pressure difference
across a curved between interface surfaces. If a concave
meniscus is formed as a result of surface tension capillarity
rising can occur, but in the case of a convex
meniscus the situation is reversed.
The penetrant is in the defect in a different condition; a
capillary tube is open to the air, while generally defects
are closed. It would seem that the case of a closed tube is
more closely similar to that of a fine short crack, than is
an open tube, because of the presence of the trapped air.
In this case, it is necessary to consider two different
conditions (Figure 2 and Figure 3).
ที่ 0 แสดงมุมสัมผัส ( คิดว่า ) จาก
มุมมองของการทดสอบแทรกซึมเหลว , 0 และ CR เป็น
ผลกระทบจากคุณลักษณะของวัสดุที่ทดสอบ ถ้า
2 ไอดีสมบูรณ์ wets พื้นผิว 19 สามารถถ่ายเป็น
zeroi เงื่อนไขดังกล่าวข้างต้นแสดงพื้นผิว
ของวัสดุ แต่ข้างในข้อบกพร่องที่ผิวของผนังที่แตกต่างกันมาก
.
สำหรับแคพิลลารี , rising energy is needed to reverse the
tendency towards reduction of surface area in liquids.
Surface tension is the energy required to increase the
surface area of a liquid by a unit amount. Thus, the
height to which the liquid rises is determined by the
surface tension and the weight of the liquid column[7581.
Liquid is not pulled up by capillarity; it is pushed up by a
pressure difference. There is always a pressure difference
across a curved between interface surfaces. If a concave
meniscus is formed as a result of surface tension capillarity
rising can occur, but in the case of a convex
meniscus the situation is reversed.
The penetrant is in the defect in a different condition; a
capillary tube is open to the air, while generally defects
are closed. It would seem that the case of a closed tube is
more closely similar to that of a fine short crack, than is
an open tube, because of the presence of the trapped air.
In this case, it is necessary to consider two different
conditions (Figure 2 and Figure 3).
การแปล กรุณารอสักครู่..