What Is The Difference of Chemical Component between 316L And 316TI？

Introduction

The 316 series austenitic stainless steel is widely used for its excellent corrosion resistance and mechanical properties in industrial piping, chemical equipment and high-end construction. Among them, 316Ti and 316L, as two typical materials of this series, often lead to confusion in material selection due to differences in chemical composition. This article systematically analyzes the difference in chemical composition between the two from the perspective of material science, and combines the application scenarios to provide buyers with the basis for material selection.

1、Basic Component Framework and Core Differences

Both 316Ti and 316L are based on “18% chromium (Cr) - 12% nickel (Ni) - 2% molybdenum (Mo)”, but the properties are differentiated by the control of the carbon (C) content and the addition of the stabilizing element titanium (Ti).

element	316L（ASTM A240）	316Ti（EN 1.4571）
碳（C）	≤0.030%	≤0.08%
钛（Ti）	-	≥5×C% and ≤0.70%
铬（Cr）	16.0-18.0%	16.5-18.5%
镍（Ni）	10.0-14.0%	10.5-13.5%
钼（Mo）	2.00-3.00%	2.00-2.50%

  

Difference Resolution.

1. Synergistic effect of carbon content and titanium

•    316L: Reduces the risk of intergranular corrosion by strictly controlling the carbon content to ≤0.03% (low carbon), reducing chromium carbide (Cr₂₃C₆) precipitation at grain boundaries.

•    316Ti: Carbon content is allowed to be relaxed to 0.08%, but a “stabilizing” effect is achieved by adding titanium (Ti ≥ 5 x C%) to preferentially combine with the carbon to form titanium carbide (TiC), avoiding chromium depletion.

   2.Fine-tuning of nickel and molybdenum

316Ti slightly increases the nickel content (10.5-13.5%) to balance the austenite phase stability, and limits the molybdenum content to an upper limit of 2.50% to optimize high-temperature strength

2、Effect of chemical composition on performance 

1. Corrosion resistance

• 316L: Low carbon design makes it still resist intergranular corrosion in welding or 450-850℃ sensitized temperature interval, suitable for long-term exposure to chlorides, acidic media scenarios (e.g., offshore platform pipelines).

  
  

• 316Ti: The stabilizing effect of titanium makes it better than 316L in resisting intergranular corrosion in high-temperature environments (>500℃), suitable for heat exchangers, high-temperature reactors and other equipment.

2. Mechanical properties

• 316L: lower carbon content leads to slightly lower strength (tensile strength ≥ 485MPa), but the ductility is better (elongation ≥ 40%), suitable for deep-drawn stamping molding process.

  
  

• 316Ti: the solid solution strengthening of titanium to improve high temperature strength (strength at 600 ℃ is 15-20% higher than 316L), but the cold working performance is slightly inferior.

3、Selection suggestions and scene matching

1. Preferred scenarios for 316L

• Corrosive environment: long-term exposure to chlorine-containing media such as seawater and bleach.

• Welding requirements: thin-walled fittings that require multiple welds and cannot be solution treated.

• Cost-sensitive: the addition of titanium increases the raw material cost of 316Ti by about 8-12%.

 

2. Preferred scenarios for 316Ti

• High-temperature conditions: working temperature for a long time higher than 400 ℃ hot air pipes, boiler components.

• Creep resistance needs: pressure equipment in the need to balance the high temperature strength and corrosion resistance.

• Thick-walled components: titanium can inhibit the tendency of grain boundary corrosion of large cross-section materials in the sensitized temperature zone.

 

4、the summary

316Ti and 316L chemical composition difference is essentially different carbon content control strategy: 316L through ultra-low carbon design to avoid intergranular corrosion, while 316Ti with the help of titanium elements to achieve carbon stabilization.

Purchasers should be based on the type of media, operating temperature and processing technology comprehensive selection of materials, corrosion resistance, strength and cost to achieve a balance.

For conventional corrosive environments, 316L is more cost-effective; if high-temperature and high-pressure conditions are involved, 316Ti is a more reliable choice.