Loại que hàn nào sau đây được sử dụng để hàn thép hợp kim Mangan và Molipden theo tiêu chuẩn AWS A5.5?

The question pertains to AWS A5.5 standards for welding electrodes, specifically for alloy steels. Each electrode type (e.g., E9018-D1, E8016-B2L, E7016-A1, E8016NM) is designed for different alloy compositions and service conditions. Understanding the chemical composition indicators (e.g., D1, B2L, A1, NM) is crucial for selecting the appropriate electrode. E9018-D1 is suitable for high-strength, low-temperature alloy steels. E8016-B2L is for Chrome-Moly steels at elevated temperatures. E7016-A1 is for carbon and low-alloy steels containing manganese. E8016NM is for Nickel-Molybdenum steels. The question implies a Manganese-Molybdenum alloy steel. While E7016-A1 is a possibility (given it handles manganese), it's not ideal. Without more specific alloy details, pinpointing the absolute best choice is challenging. If forced to choose from the given options, E7016-A1 might be the closest, though not perfect.