c) HydrofLuoric Acid: Drink water to dilute acid, then cause vom-iting by placing finger in the back of throat. Repeat. Wash
out mouth repeatedly. Call Medical immediately.

d) Nitric Acid: Do not induce vomiting. Drink large quantities of
water, if possible. Call Medical immediately.

e) Tricresyl Phosphate: Cause vomiting by placing finger in the
back of throat. If necessary, have victim drink water, then
use finger to induce vomiting. Call Medical Immediately.

Volume 1

20-40-00
Page 3 OCT 01/01
3. Corrosion Damage and Rework Limits

A. Corrosion evaluation will be required after initial inspection and cleaning
to determine nature and extent of repair or rework. It is difficult to
establish a distinct and specific dividing line between various conditions,

consequently, the first requirement for evaluation is good and sound mainte-nance judgment. Evaluate corrosion as follows:

(1)Light corrosion -Characterized by discoloration or pitting to a depth
of approximately 0.001 inch maximum. This type of damage will normally
be removed by light hand sanding or a minimum of chemical treatment.

(2)Moderate Corrosion -Appears similar to light corrosion except there may
be some blisters or evidence of scaling and flaking. Pitting depths may
be as deep as 0.010 inch. This type of damage will normally be removed
by extensive hand or mechanical sanding.

(3)Heavy (severe) Corrosion -General appearance may be similar to moderate

corrosion with severe blistering exfoliation and scaling or flaking.
Pitting depths will be deeper than 0.010 inch. This type of damage will
normally be removed by extensive mechanical sanding or grinding.

B. Degree of Corrosion Damage. A preliminary assessment of corrosion damage is
sometimes advisable before cleanup to determine whether there is any chance
of reclaiming the part. Where damage is obviously in excess of allowable

limits, repair or replacement action should be initiated.

C. Previously Reworked Areas. Allowable damage data is normally based on a loss
of material thickness, however, this must also include any loss in thickness
due to previous rework. Previous rework can be ignored if the actual thick-ness remaining after corrosion cleanup is measured. Suitable NDT equipment

(such as eddy-current or ultransonic instruments) is recommended both for
crack detection and thickness measurement.

D. Depth Measurement Using Straightedge. Depth measurement is often possible
using a straightedge and a 10-power magnifying glass as shown in Fig. 1. The
straightedge should be placed at various angles to ensure that incorrect

measurements are not recorded due to local surface irregularities.

E. Measuring Corrosion Damage with a Dial Depth Gage. The method for taking
measurements with a dial depth gage is outlined below:
　
中國航空網 m.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：757 防腐手冊 CORROSION PREVENTION MANUAL 第二冊 一般信息(18)