Question

identify the 1 in the aws classification for mild steel electrodes.

hydrogen level in ml/100 g
welding position
minimum tensile strength in ksi
indicates impact requirements
electrode
type of coating and current
indicates requirements of absorbed moisture test

e7018-1 h4r

Explanation:

Analyze the AWS electrode classification system

Using the AWS Electrode Classification knowledge point

• E: Electrode
• 70: Minimum tensile strength in ksi (\(70,000\text{ psi}\))
• 1 (in E7018): Welding position (all positions)
• 8: Type of coating and current (low hydrogen, iron powder, AC or DCEP)
• -1 (the highlighted digit in E7018-1 H4R): Indicates impact requirements (improved toughness/impact properties at lower temperatures)
• H4: Hydrogen level in ml/100 g (less than \(4\text{ ml}/100\text{ g}\))
• R: Indicates requirements of absorbed moisture test (moisture resistant)

Identify the highlighted digit

Using the AWS Electrode Classification knowledge point

• The highlighted digit is the 1 following the hyphen in E7018-1.
• In AWS A5.1 specifications, a suffix of "-1" on an E7018 electrode designates that the electrode meets optional supplemental requirements for improved toughness (impact energy requirements at lower temperatures).

Answer:

• Hydrogen level in ml/100 g
• Welding position
• Minimum tensile strength in KSI
• Indicates impact requirements (Correct answer)
• Electrode
• Type of coating and current
• Indicates requirements of absorbed moisture test