Reconciliation of Materials (Part-1)

Dear Readers,

Wish You a Happy Engineers Day

Materials reconciliation is playing vital role in construction industry. It is directly linked with contractual related. If we are not taken properly it will have a huge impact on project cost. However based on the proper documents and proper method we can come out this difficulties. Considering the contents it will be blocked in two or three parts.

•       What is meant by reconcile?

o   Getting two things to correspond / agree

•       Reconciliation

o   Reconciliation is the process of ensuring that any two related values agree after taking in to consideration the data relating to possible variance

o   Theoretically we can reconcile any two values whose relationship can be expressed in the form of a mathematical equation.

o   For Material reconciliation, it is the process of comparing the standard data with actual data after considering data relating to variances. (Difference between Theoretical Consumption Vs Actual Consumption)

o   Result of reconcile is either wastage or Savings

•       Basic Components for Reconciliation

o   Raw Material Receipt

o   Raw Material Stock

o   Raw Material Issue

o   Consumption of Material

Will be Continued....

Hardness of Bolt

Dear Readers,

Generally the grades of bolts are starts from 4.6 to 12.9. Also known as Ordinary bolt (Commercial Grade),  HT Bolt (High Tension) & HSFG Bolts (High Strength Friction Grip). 

The bolt designation system is based on two numbers. The first number represents the ultimate tensile strength of the bolt, 400 MPa, 800 MPa or 1200 MPa respectively. The second number represents the point at which the bolt will permanently stretch. A 4.6 grade bolt permanently stretches at 60% of its ultimate, an 8.8 grade bolt at 80% and a 12.9 grade bolt at 90 % of its ultimate.

Technically it can be quoted that the first number is the tensile strength of the bolt material (N² )/100. 

The second number is = 1/100.(the ratio of the Proof (or Yield ) stress and the Tensile strength expressed as a percentage = 100.[Yield (Proof stress) /Tensile strength] /100

For Example the tensile and proof strength of the steel for a 8.8 bolt is therefore calculated as follows

Tensile strength = 8 X 100 N/mm² = 800 N/mm² and Proof strength = 0.8*800 * 100 /100 = 640 N/mm² (generally speaking 80% of 800N/mm2)

The lowest grade is 4.6, commonly known as commercial grade. Next comes grade 8.8, known as structural grade, and finally, the highest grade is 12.9, known as HT / HSFG bolt. 

Available grade of bolts are 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9 & 12.9

Generally foundation bolts are made from 4.6 or 4.8 Grade

Hardness of bolts are as follows

Specific Gravity

As you well aware that all materials having individual properties and weights based on the density. How we can compare the different materials in a same platform. Since water has a density of 1 gram/cm3, and since all of the units cancel, specific gravity is the same number as density but without any units (adimensional).

A 1000kg of pure water = 1 cubic metre. Pure water was chosen as the 'base line' for specific gravity and given the value of 1. The specific gravity of all other materials are compared to water as a fraction heavier or lighter density. For example, beryllium has a specific gravity (sg) of 1.84 (1840 kg/cu.m) 

As specific gravity is just a comparison, it can be applied across any units. The density of pure water is also 62.4 lbs/cu.ft (pounds per cubic foot) and if we know that a sample of aluminium has a sg of 2.5 then we can calculate that its density is 2.5 x 62.4 = 156 lbs/cu.ft.
Note, kg/cu.m divided by 16.02 = lbs/cu.ft

One handy metric link between units to remember is that 1 Litre [1000cc] of pure water weighs 1 kilogram. Equally, 1 millilitre of pure water has a mass of 1 gram or 1mL = 1g. The upper-case L for litre is preferable as the lower case can be confused with the figure one, however it is common to see ml for millilitres on bottles.