vernier height gauge, wrought iron, ferrous and non-ferrous metal

Vernier height gauge-

1- Vernier height gauge is a precision instrument.

2-  It is marking and height measuring instrument .

3-  Its accuracy is 0.02mm or 0.001inch.

4-  It is also used for measuring depth, with a depth attachment.

5-  Its parts is Beam , Base,  Main slide,  Jaw,  Jaw clamp,  Vernier scale,  Main scale,  Finer adjusting slide,  Finer adjusting nut,  Locking screws, L Scriber blade.

6- Vernier height gauge is made of invarsteel/ stainless steel.

Care and maintenance of vernier height gauge

1-It should be used by placing on surface plate.

2-Surface plate should be properly cleaned.

3-Reading should be noted down to avoid mistake.

4-When scribe bottom surface contact surface plate level then zero lines of vernier scale should contact with main scale, the zero reeor should be adjusted.

You should regularly cheek the calibration of your height gauge, to make sure that it is working correctly.

Wrought iron and plain carbon steels-   

1-It is purest from of iron

2-It contains 99.99% iron.

3-It is used for dynamo, agriculture tool, ship outer parts, steam and water pipe,railway coupling, nut and bolt etc.

4-It is made by two process puddling process and aston process.

Puddling process-

              1-Wrought iron is manufactured by refining pig-iron.

              2-refining pig-iron silicon is removed completely,

    3-a greater amount of phosphorus is removed, and                

        graphite is converted to combined carbon

   4-The above process is carried out in a puddling furnace.

Aston process-

1- In this process molten pig-iron and steel scrap are refined in a Bessemer converter.

2-The refined molten metal is poured into an open hearth furnace in the iron silicate stage. This removes most of the carbon.

3-The slag cools the molten metal to a pasty mass which is later squeezed in a hydraulic press to remove most of the slag.

Rectangular blocks known as blooms are formed from this mass.

4-The hot bloom is immediately passed through rolling mills to produce products of wrought iron of different shapes and sizes

steel

1-Steel is fundamentally an alloy of iron and carbon

2- with the carbon content varying up to 1.5%.

3-The carbon present is in a combined state
4  Plain carbon steels are classified according to their carbon content.

Name of the plain steel	Percentage of Carbon	Properties and uses
Dead mild steel	0.1 to 0.125 %	Highly ductile. Used for making wire  rods, thin sheets & solid drawn tubes
Mild steel	0.15 to 0.3%	Relatively soft and ductile. Used for general workshop purposes, boiler plates, bridge work,structural sections and drop forgings
Medium carbon	0.3 to 0.5%	Used for making axles,drop forgings, high tensile tubes, wires and agricultural tools
-do-	0.5 to 0.7%	Harder, tougher and less ductile.Used for making springs, locomotive tyres, large forging dies, wire ropes, hammers and snaps for riveters
High carbon steel	0.7 to 0.9%	Harder,less ductile and slightly less tough.Used for making springs, small forging dies,shear blades and wood chisels.
-do-	0.9 to 1.1%	Used for making cold chisels, press dies, punches, wood-working tools, axes,etc.
-do-	1.1% to 1.4%	Used for making hand files, drills, gauges,metal-cutting tools & razors

    .

Non-ferrous metals-

1-   These metals do not have any iron contents and not attracted by magnet are called non ferrous metal.

2-  Type of non- ferrous metal is copper, aluminium,  znic  , tin, lead, nickel, chromium,  etc.

Copper- 1-Its ores ‘MALACHITE and ‘PYRITES’

      2-Reddish in colour

      3-It is very malleable and ductile and can be made into                

          sheets.or wires

4- It is a conductor of electricity.

2-  brass- alloy copper and zinc .bronze-alloy copper & tin

3-  The melting temperature of copper is 1083o C.

4-  Copper is a good conductor of heat and also highly

      resistant to corrosion.

Lead- 1- Lead is produced from its ore ‘GALENA

             2- Lead is a heavy metal

         3- Silvery in colour when molten

             4-  Lead is resistant to many acids like sulphuric acid and  

                 hydrochloric acid  

5-  Babbita metal alloy of lead,tin,copper 

6-  It is used in car batteries and An alloy of lead and tin is used as ‘soft solder .

7-  Melting point is 330 o C.

Zinc-  1-    Zinc is obtained from the ore-calamine or blende

    2 -  Its melting point is 420o C.

    3  -  It is also corrosionresistant.

            4  -  It is used for battery containers and is coated on                          

                    roofing sheets etc

    5 - Galvanized iron sheets are coated with zinc.              

Tin –

1-  Tin is produced from cassiterite or tinstone

                It is silvery

2-  white in appearance.

3-  the melting point is 231o C.

4-  soft and highly corrosion-resistant.

5    - It is mainly used as a coating on steel sheets for the

       production of food containers.

          Example: Tin with copper to form bronze. Tin with lead to

          form solder. Tin with copper, lead and antimony to form

Babbit metal

 Aluminium-  1- Its iron ore is ‘BAUXITE

                  2 - Aluminium is white or whitish grey in colour

                 3 - Has a melting point of 660o C