• Improper welding of X80 pipeline may cause cracks
• Brief introduction of API X52 pipeline steel
• The difference between PSL1 and PSL2
• Harm of inclusions in X70 pipeline steel
• API 5L pipeline pipe
• X52 steel plate surface quality standards that need to be met
• The basic production process of API 5L X60 pipeline steel
• The key to Q460D steel welding process
• What does the heat treatment of Q690 Steel include?
• Reasons for choosing Q690D steel

Harm of inclusions in X70 pipeline steel

Inclusions in X70 pipeline steel mainly exist in the form of non-metallic compounds, such as oxides, sulfides, nitrides, etc. Non-metallic inclusions have a great influence on the strength, plasticity, toughness and other properties of X70 pipeline steel. Generally, only when the size of non-metallic inclusions is less than 1 μm with small number, and the distance between inclusions is greater than 10 μm, it will not affect the macroscopic properties of X70 pipeline steel. Al2O3, MnS and calcium aluminates are the main inclusions that have a great influence on the properties of X70 pipeline steel.

The cleanliness, type, size and quantity of X70 pipeline steel have a very significant impact on the toughness and HIC resistance of X70 pipeline steel. Simply improving the cleanliness cannot improve the strength of X70 pipeline steel, but improving the cleanliness can greatly improve the impact toughness of X70 pipeline steel.